Commercial Aquaponics Systems FAQ

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   What is aquaponics?

   It is growing fish (aquaculture) and growing plants in water (hydroponics), combined into a recirculating aquaponics system. There are many systems that claim to be aquaponics but simply use fish tank or pond water to irrigate plants; usually a good idea, but not the same thing at all.

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   Is aquaponics difficult to learn or hard to do?

   It would be, if you had to reinvent it yourself. Because there is a large body of usable knowledge available, and many successful practitioners willing to share their knowledge, learning aquaponics is easy. It's kind of like math; when you first started working with those numbers (remember, you were only three feet tall?), it was hard adding 3 and 6. Now you do it without thinking about it.

   In practice, it's just feeding the fish, planting and harvesting the vegetables. We don't spend much time thinking about the nitrifying cycle or ammonia levels. Even if we did, those things are simple to measure and understand. The hardest thing we've found about aquaponics is that so many people are interested in it. We had to start giving regular farm tours every Saturday because we had fifteen to twenty people showing up at odd times during the week to see our farm, and so far over 1,000 people have come to see the farm since we started giving tours in June, 2008!

   Remember, we are not farmers, or even gardeners. This is a really easy food production method - so easy that we don't like to use the word "farming" to describe this; as that word is automatically associated with hard physical labor.

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   What is the most important thing to know about aquaponics?

   That it's not about raising fish! Although the fish in aquaponics systems attract the most attention, the fish portion of the operation is costly both in terms of consumables and labor, and does not produce a profit unless combined with the vegetable income. Based on our last two years experience with commercial systems, the fish portion brings in 8% of the total income, while the vegetable portion brings in 92%. The problem with this is that the fish part of the operation creates a large percentage of the operating costs, for fish food, electricity for aeration, and labor for feeding, breeding, and harvesting the fish; while bringing in the small income percentage noted.

   When you try to grow MORE fish in the temperature range we are farming in (70-76 degrees F), with the fish food costs we have ($0.90/pound), the electricity costs we have ($0.44/KWhour), and the labor costs we have ($12/hour or more), EVEN with the price we're getting for our fish ($5/pound) the more fish we try to grow, the MORE money we LOSE on the fish part of the operation. This means that if you are considering commercial aquaponic production, you should get accurate numbers for fish production from a farmer in your area rather than just stick an income number into your spreadsheet. If you ever hear a consultant who tells you can grow "X" amount of fish in the system they design, you have just heard a completely misleading statement; because the amount of fish you can grow in any system is entirely dependent on the system water temperature (plus MANY other factors they often forget to mention). Aquaculture businesses that have failed outnumber those that survived by ten to one.

   A lot of people selling aquaponics system information or "kits" know how important the fish production is to potential operators, and often vastly over-state the amount of fish it is possible to grow with these systems (they all too often over-emphasize the vegetable production too), in an attempt to appeal to buyers and sell more stuff. If you hear these kinds of claims, ask the sellers to back them up with phone numbers of real users you can call to verify the claimed "fish production" and "vegetable production". You can't ever get something for nothing, or as a famous author once wrote: "TANSTAAFL!"

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   What kinds of aquaponics systems are there?

   There are all kinds of aquaponics systems out there. It is important to be able to discern which is which:

   Experimental systems: Useful experimental systems are put together with best current knowledge of aquaponics technology using established scientific methods to investigate a new idea. If the hypothesis being investigated in the experiment proves out by improving production and efficiency, or lowers the cost of a system, it is no longer an experimental system, but a successful next-generation system. If the experimenter is not using current knowledge and good scientific procedure, you may have a voodoo system, not an experimental system.

   Hobby Systems: A system built and operated with no requirement for financial return is a hobby system. Even if you want a hobby system rather than a commercial one, being well-informed about aquaponics will ensure that you have a good hobby system that is fun to own and operate, rather than a money-sucking, bad-smelling, backyard disaster on your hands.

   Demonstration Systems: A demonstration system shows how the principles of aquaponics work, and is not necessarily a profitable system, or even one that is stable over time. One might see this type of system in a school, for instance, where they wanted to teach aquaponics but could not afford or did not want a system that would require tending. Not everyone needs the 300 pounds of produce and 5 pounds of fish a week a system of a couple hundred square feet can grow. We have built a tabletop demonstration system and use it at public events, but we do not rely on it to grow the food that we eat.

   Useful Systems: A useful system is one that pays its operating costs (fish food, electricity, seeds and planting media). We offer plans for three different sizes of systems that satisfy these criteria. Whether it's a commercial system, a large family system or a micro aquaponics system, they all grow the same amount of vegetables for each square foot of raft area. A good way to determine if a system you're considering building will produce is to get references from someone who has run one (not just the sellers of the "kit") and see if it meets your needs.

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   I already have a pond/tank/swimming pool. Can I use it as part of a recirculating aquaponics system?

   A recirculating aquaponics system is a complete system, just like a car is a complete system. A car works because it is complete and has all its parts. If you just have the front wheels of a car, it doesn't do you any good. In the same way, only having a pond/tank/swimming pool doesn't do you any good if you don't understand how aquaponics systems work. You've only got part of the system.

   It is theoretically possible to use a pond as part of an aquaponics system. You will have some problems: the nitrifying bacteria that make a recirculating aquaponics system work are light-sensitive and may get killed off or severely inhibited by the light entering a pond, therefore you will need to shade your pond. You will probably need to mechanically aerate your pond to attain reasonable dissolved oxygen levels (DO). Harvesting fish out of a pond requires a seine net, a wetsuit and booties, and a much larger labor commitment than harvesting out of a tank or raceway.

   If your pond has flow-through water from a source such as a spring or creek, you will need to disconnect it from that source, install a recirculation pump and hydroponics of some sort, then shade the pond to even have a chance of it working. Flowing water through the system from your source (then dumping it out the far end of the hydroponics) won't work because the continually flowing water will dilute any nutrients the fish do deposit into the pond to a level that will probably not do the plants any good.

   People also ask if they can just put the rafts on top of the pond or tank. Except for the fact that a fish tank or pond can support about ten times the area of hydroponics trough as fish tank area, this idea will work IF you figure out a way to protect the vegetables from being eaten by the fish, and a way to feed the fish when the top of the tank is covered with hydroponics rafts, then it might work, and you might get one-tenth the amount of vegetables you would get with the same size fish tank and amount of fish put together with the proper amount of hydroponics. But this is doing it the hard way.

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   I already have a pond/tank/swimming pool. Can I just use it to grow fish without having to do this aquaponics stuff?

   Again, this is about understanding the system. Fish need several things to flourish and grow, just as any other animal does. The first thing that limits fish growth and production is usually dissolved oxygen levels (DO). This is the amount of oxygen present in the water that is available for the fish to breathe. If the fish are having trouble breathing because DO levels are low, they get stressed and don't feed or grow well. Bringing DO levels up requires mechanical aeration or flowing LOTS of water through the system. If you flow-through, the water needs to be naturally aerated (well water often won't work), and you need to put from 10% to 200% of the total system volume through PER DAY to keep the fish happy, depending on how many fish you have in your pond/tank. In other words, you need free water in order to do this. If you don't have free water, a mechanical aeration system of some kind is necessary to get enough air to the fish.

   The next thing that limits fish growth and production (after you solve the aeration problem) is water quality. The fish effluent in a well-aerated (but stagnant) pond or tank has nowhere to go, and the fish get stressed and die. It's as if your bathroom was in the corner of your living room but there was no toilet. It would get pretty pungent after awhile and you would move out or do something about it. But the fish can't. So it's necessary to clean the water somehow. This is the situation that led to aquaculture pioneers inventing biofilters for recirculating aquaculture systems (which still require 10-20% of new water a day to work), and then led to aquaponics pioneers inventing recirculating aquaponics (which doesn't).

   As an example, a 3,000-gallon fish tank with no aeration and no biofiltration might support 40 to 50 1-1/2 pound fish; the same tank with the optimum amount of aeration added might support 80 to 100 fish, but the water quality would get iffy; the same tank included as part of a recirculating aquaponics system with optimum aeration supports 1,000 1-1/2 pound fish. We know, we have several like this. So the answer to this question is about understanding the system. You can't raise fish economically in stagnant ponds or tanks.

   One more thing: depending on the fish species you have, there may be more factors in play that just these. We raise tilapia, which will breed like crazy in an open pond. After a year or two, what you'll have in an open pond situation with these fish is a bunch of 6-to-8-inch long fish, a FEW one-pound size (Biggies!), and a lot of little fish getting eaten by whatever's around, including their larger siblings. However, if you know tilapia psychology, and crowd them by putting a lot of them in a tank or in cages in a pond, they stop breeding activity and get fat instead. Because breeding consumes food and doesn't promote fish growth, by stopping it you will get fish growth and better utilization of the feed you feed them.

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   Can I do aquaponics with pigs/chickens/rabbits, or include them somehow in my aquaponics system?

   The problem here is E. Coli. For humans, there are 13 very irritating strains of E. Coli and one that can kill us. All come from warm-blooded animals (pigs/chickens/rabbits), which fish are not. Although there is E. Coli everywhere, and there are thousands of different strains, the ones fish generate are not the ones that harm humans. I know, I drank a couple of quarts of aquaponics system water. It was lucky I told my wife (the biologist), after I drank the water, she would have squashed the idea flat if I'd told her before.

   There is really no way to include these animals in an aquaponics system. The standard organic rules for animal manure require that a field have at least 120 days between the last application of animal manure to it and when harvesting occurs in order to safeguard the consumer's health. So you can use these animal manures safely in dirt farming if appropriate times are observed between manure applications and harvesting.

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   How often do you exchange the water in the system or have to sterilize it?

   Because the recirculating aquaponics system is a dynamic mini-ecosystem, it has a tremendous degree of stability. When changes occur in pH, nutrient level, ammonia levels, and other indicators, they change slowly over a period of days or even weeks. When changes do occur, such as pH getting increasingly acid, the correction is easy to administer. We have never had a fish or plant disease episode in three years of operation in the tropics.
   Our current two-part hypothesis explaining this is:
   1. Because the water quality in the recirculating system is so high (low levels of ammonia, nitrites, and nitrates, and a high level of DO) the fish are supported in having naturally strong immune systems, and
   2. Because the plants are getting an organic, chemically complex nutrient solution from the fish effluent water, they are healthy and don't develop or harbor diseases as easily as hydroponic plants grown with man-made chemical nutrients do.

   This question is usually asked by those with experience in hydroponics, where systems often have to have water exchanged and be sterilized in order to prevent rampant plant disease problems. When Dr. Rakocy (UVI) goes to hydroponics conferences, the other attendees (people with years of experience in hydroponics, but no aquaponics experience) refuse to believe him when he says he has never exchanged his system's water or sterilized it.

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   How do I get the fish to start my aquaponics system, and how do I get them from the hatchery to my location?

   Here are the applicable sections from our course manual: You don't need tilapia at first if they're hard to get, even if that's what you plan to grow. You can put in a mixed bunch of koi, catfish, and tilapia, as long as the smallest ones you put in are not so small that they are edible by the biggest ones you put in. The vegetables are 90% of your income anyway, you only need fish to excrete in your system to provide fertilizer for the plants. Sort them out later with a net and have a barbecue. If you are not in Hawaii, there are many other species of fish that are cultured commercially, grow quickly, and can easily handle the water quality of aquaponics systems. Species that would work well are yellow perch, bluegill, crappie, large mouth and small mouth bass. In Australia or elsewhere in the world there are with wild-sounding names we only barely know about that would work just fine.

   Check with your local aquaculture extension agent at the local University; they will be able to give you the names of aquaculturists' in your area you can purchase fingerlings from.

   You just need to be a little inventive to get them (alive and in good shape!) from the fish hatchery to your place. They need water, and they need air. The simplest way is to borrow a friend's pickup truck, lash a couple of heavy-duty garbage cans in the back (make sure they have good lids!), and get yourself a couple of 12-volt bait-bucket bubblers with the bubbler tubing fed through a small hole in the lid of the trash can. Put water from the aquaculturists' tanks into the trash cans (NOT fresh chlorinated water; you'll choke the fish!), put a MAXIMUM of 15 lbs of fish or so into each trash can, turn the bubblers on (make sure the airstones are well-sunk to the bottom of the trash cans and are emitting a good solid stream of bubbles), lash or tape the lids solidly onto the cans, and head for home!

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    Whom do I trust for aquaponics advice?

    Consultants will try to sell you consulting; amateurs will stun you with their lack of knowledge; and academics want more than anything to get that next paper in a prestigious publication. They all have their good points: a good consultant can solve an expensive problem cheaply; amateurs started the aquaponics movement in the first place (they were ALL amateurs back then); and there is an amazing amount of good information available thanks to all the academics who have studied and published over the years.

    Professional aquaponicists are people who make a living from operating aquaponics systems. They combine the best traits of consultants, amateurs, and academics with the ability to figure out how to make things work at a profit. A professional often has more practical and useful advice to offer than a consultant, because they have more hands-on experience with the subject. A professional exhibits the most valuable trait of amateurs: an amateur will try anything. The professional has the willingness to give unlikely things a try, guided by their knowledge. And a professional is always interested in the next bit of knowledge and understanding, just as academics are. The difference is that the professional's focus is on the bottom line, and how to make their efforts more profitable. True sustainability is when you're still in business a year from now.

    When you're listening to someone talk aquaponics, see if you can figure out their angle and interest in the subject. If you know, then you can filter out and separate the useful and economically sound information from the sales pitches, dumb ideas, and too-complex-to-be-useful data.

    If you are going to invest your time and money in an aquaponics project, then check out existing operations first. A lot of "Aquaponics" on the Web is computer-generated renderings of greenhouses and fish tanks showing systems that have never been built. If that's all you need, there are cheaper places to get them than these sites, and many places to get better information too. Actual pictures of the UVI aquaponics system on their website was what got us into the UVI Short Course in the first place. Every photo you see on our website was taken at our farm, and is something we built and operate ourselves.

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    Other than overwintering fish indoors what else would need to be changed for a colder climate like Minnesota?

    This question is covered in the Micro System manual starting on page 36 "Climate's Effect On System Operation, and How To Adapt To It". If you do not want to go to the expense of a greenhouse as this section suggests, and only want to grow during your normal growing season, overwintering the fish is the simplest option. Regardless of the species of fish, here's what this requires: the fish need to be kept in water that is slightly warmer than their "minimum temperature range" so that they will continue eating and survive the winter, and they need to be aerated sufficiently. This means the fish tank can be inside an insulated and perhaps heated structure, and the tank water not being circulated during the winter. You would need to exchange about 50% of the water in this non-circulating fish tank per week or so during the winter to remove excess ammonia, nitrites, and nitrates, but if the fish are not kept too warm, they won't metabolize much and won't create much waste . The tank water would be pumped out to the hydroponics troughs again during growing season. This minimum temperature can be hugely different for different species of fish. Unfortunately there's no way we can test different species in Hawaii as we are only allowed to legally raise a small selection of the fish species that are available on the mainland.

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    Is aquaponics possible in a cold climate such as New England?

    It is not only possible, it 's possibly the only method of agriculture that is economically viable in cold climates year-round. This is completely covered in the Micro System manual starting on page 36 "Climate's Effect On System Operation, and How To Adapt To It", and also in another question posted in this FAQ that starts with "Other than overwintering fish indoors.....".

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    How many pounds of tomatoes are you harvesting from one plant? Have you tried bush beans, and if so, how did you do and what was the yield?

    We found out tomatoes need a screenhouse to keep the pests from decimating them, but we also found three varieties of tomatoes that were pest-resistant. One of these, a large sweet yellow cherry tomato, gave about 200 lbs of tomatoes in 3 months from a single plant! We had mixed results with bush beans; both limas and fava beans made huge bushes, flowered, but didn't set beans. Right next to them we had purple beans, French beans, yellow wax beans, and regular green beans that did just fine.

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    What can I feed tilapia besides commercial fish food?

    We've tried two species of locally available duckweed; the tilapia don't eat it and it's a pest in the hydroponics troughs. We tried black soldier fly larvae; the larvae are heavier than water and they sink, and the tilapia are hardwired to ONLY eat things that float; they just sat and looked as the fly larvae slowly sank past them. The answer to this one is very specific to the species of fish you are growing as each one is different. Be careful experimenting with growing things in your aquaponics system for your fish to eat; for instance, if you EVER get a crawfish in there, they will be the ONLY things you are growing because they eat everything else!

    We have heard from one of our students (who is obviously NOT allergic to work!), that she raises black soldier fly larvae and duckweed; dries the duckweed, then grinds up the larvae and duckweed together to make fish food, which HER tilapia enjoy and eat enthusiastically. There ARE ways to feed these fish without using commercial fish food, but you have to ask yourself: "How much time am I willing to give this?".

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    What size and type of net pots do you use? Do you transplant out of them when they get crowded in these pots? In your manual, it seems that you just place the whole thing in the raft? But don't they crowd in their own pot?

    We use Poppelmann 2" net pots for most species, and 3" for a few (tomatoes, leeks, green onions). The 2" are available in cartons of 5,000 for about $200 here in Hawaii. The seedlings NEVER get transplanted out of the pot they start in, they just go into the rafts from the sprouting tables when they are about 2" tall.

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    I live in the Sierra Nevada foothills of Northern California at 2000' elevation. The winter low average temp is 30 deg F and the summer hi average temp is 100 deg F. What type of fish and/or crustaceans do you recommend for such a climate?

    Great general question about the "engine" that powers your aquaponic system! The answer is to use what aquaculturists in your area are already successfully using. If you cannot find an aquaculture farm or fish farm in your area, or if they don't want to answer questions or sell you fish, then contact the nearest big State University with a good Agriculture Department. They usually have aquaculture Extension Agents whose job is to help you get started and get successful growing fish, and the agent can tell you all kinds of information about who is growing what and how successfully, in your area. Don't try to grow stuff that doesn't already grow well in your area unless you have a trust fund!

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    Hello, can I grow carrots?

    Great question! We haven't grown carrots, but we HAVE grown onions, beets, kohlrabi, radishes, Hawaiian taro, turnips and parsnips. They all grow up onto the top of the potting coir in the pot. We had one turnip that weighed 2-1/2 pounds and had about 2 feet of greens; both the greens and turnip were sweet, tender, and delicious!

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    Hi I wanted to attend the next group training but have a scheduling conflict. I notice you now offer a commercial system plan. While I'm aware that nothing compares to personalized training I am curious about the the plan. Is the plan as comprehensive as the training on technical grounds? Can the commercial plan be scaled up efficiently and are there instructions included on how to do this. Thank you kindly. Russell

    Our Do-It-Myself Commercial training packages use exactly the same course materials we use in our live Hawaii Group and Personal Intensive trainings. If you purchase one of the DIM packages then decide to do either of the live trainings, we will credit the purchase price of the DIM package towards the regular training price. We've done everything we can to make these packages as helpful as possible to those who can't attend a live training, so they can duplicate what we've done here without needing to come to Hawaii.

    To answer your second question, larger aquaponics systems give you better energy efficiency and work process efficiency. The commercial DIY package contains complete instructions on how to scale-up an aquaponics system to whatever size is required, including instructions on how to size water pumps, water pump lines, and air blowers and air distribution system.

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    Is electricity needed and if so, how much and why.

    Our "Small Commercial System" with 4,156 square feet of grow bed area uses 650 watts 24/7. Smaller systems that are scaled-down from this one should consume a proportionately similar amount of electricity, depending on what the consumption of the blowers and pumps in the correct size range is. This is because when you scale a system, you sometime need to buy a blower or pump that gives you more than you need and consumes more electricity than optimal, because the next smaller available one is too small for the job. We are doing research into ways to improve electrical efficiency both for water pumping and for aeration, but for now, we've reduced the needs of the systems we designed down to only 18% of the electrical consumption of the original University of the Virgin Islands systems we learned on.

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    Tim, you state you use floating catfish food to feed your fish. How do you feed your Fingerlings and Fry? I crushed a pellet, tossed it in and about 2/3 of the powder sank.

    We always use whole pellets to feed our fish. We originally fed our fry and fingerlings crushed food as you did, and had the same experience with the food sinking. When it sinks, it just turns into decaying organic material and then ammonia, except we still have to pay for it. We found that when the very small swim-up fry were fed the floating food, they could easily eat it after it had become soaking wet and soft. They sort of "dink" around all the edges and the food pellets disappear. We've been doing this for two years now.

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    Are you planning on trying foods aside from fruits? Have you tried grains and other such organisms? How is this system progressing in the commercial world, aside from home systems?

    We are going to be experimenting with grains soon. One of the biggest criticisms of aquaponics systems has been that they historically only have been used to grow leafy vegetables such as lettuce and basil. Neither of these are really "food", but rather an interesting side dish or herb flavoring you can eat along with a main dish of protein and grains. We need to find ways to grow protein and grains with aquaponics systems. Tomatoes, melons, beans, and strawberries all grow exceedingly well in these systems, and one of those will be our next cash crop after we have saturated the lettuce market (what we're currently growing).

    The system is progressing just fine in the commercial world, with (as of 5-6-2010) fifteen commercial-scale systems that we know of having been built by students of our courses. Three of those systems have been USDA organically certified following the guidelines given in the course, by our organic certifying agency, Oregon Tilth.

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    Does our course material go over all the different kinds of edible freshwater life that is usable in aquaponics system? Can you use saltwater and grow sea life?

    Our course material covers different types of fish, some in more detail than others (because in Hawaii we are limited to a few species by import regulations), and freshwater prawns grown in aquaponics systems. We are planning on building two small test saltwater aquaponics systems later this year to try out saltwater vegetables, which have a good market in the large Asian and Pacific Island communities in Hawaii. Saltwater fish are difficult to breed in captivity, so we may simply be reduced to live-capturing wild fish and using them in a saltwater aquaponics system as fertilizer generators.

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    Wouldn't you have to add nutrients for fruiting plants and how does that affect the fish?

    The only nutrients we add to our systems (because of their USDA organic certification) are the OMRI-approved ones iron chelate and calcium carbonate. The iron remedies the iron deficiency generated by the fish utilizing all the iron contained in the fish food (which means none passes out to the plants). The calcium carbonate is added once every three to six months to buffer the pH in our systems, which gradually decreases to lower pH numbers over time. This addition, besides raising the pH back up to 7.0 or thereabouts, also provides more calcium for the plants, as the fish tend to use all the calcium available in the fish food for bone and scale growth.

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    The most common ratio of tank to grow bed seems to be 1:1 in most aquaponics systems I've read about. If I build a flood-and-drain system using an autosiphon and use a 100 gal. tank and a pump that pushes 100 gph, at some point most of the water will be in the grow bed with the fish running out of water in the tank before the grow bed begins to drain the water back in the tank. What am I missing?

    Our systems are all deep-water culture raft systems, and don't use flood-and-drain, which can create huge (read expensive!) problems in a commercial application of aquaponics. That is why this technology is most commonly used in small backyard systems where costs and productivity don't matter as much. We look at this whole subject of "ratios" differently, and recommend a ratio of 0.3 lbs of fish per square foot of raft area; about 4 gallons of fish tank volume per pound of fish in the fish tank; and 1.5 cubic feet per minute (cfm) of air @ 40" of H2O supplied by your blower for every 100 lbs of fish in a system. This aeration may need to be increased if your water is warmer than our 70-76 degrees F range, as the fish need more oxygen at higher water temperatures, and also because the water "lets go of" oxygen more easily when the temp is high.

    So, in a typical 4,156 square foot "small commercial system" of our design, we will have about 1,200 pounds of fish in a 5,000 gallon fish tank with about 18 to 20 cfm of air @ 40" H2O air pressure being supplied by the blower. This system has 4,156 square feet of grow bed area, or about 30 times the area of the 12' by 12' fish tank that holds all those fish. Aquaponics systems with roughly the same amount of grow bed area as tank area are growing way less vegetables than they could if they were sized properly (assuming they used the above ratios we developed in three years of commercial operating experience).

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    Do you only use PayPal or can I use a credit card to pay for this?

    You can sign up with PayPal, which simply means filling in an application and selecting a password, then you can use any credit card you wish to pay through PayPal. Although it had a bad reputation due to some hacking of accounts when it first came on-line long ago, PayPal now is as secure a method of payment as any available online.

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    How do nuclear submarines obtain oxygen and remove carbon dioxide from the air??

    I honestly never expected to see a question like this on an aquaponics website. Nuclear subs probably have million-dollar CO2 scrubbers and generate the oxygen chemically from some storable compound, or from large compressed-air tanks. Not having the security clearance to access nuclear sub design info, this is all I can give you at this time. (Honestly, we did not make this question up; it was submitted by one of our website visitors!).

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    The fish food and chemical compounds added to the aquaponic system(to adjust the pH and satisfy the plants need of Ca and K)are not organic.So how could vegetable and fish produced in aquaponic system using these get organic certification?

    First, look at FAQ number 52 "Wouldn't you have to add nutrients for fruiting plants and how does that affect the fish?". We only use additives that are approved by OMRI (Organic Materials Review Institute), the independent body that handles such approvals. Our organic certifying agency, Oregon Tilth, approved our organic certification as an aquaponics farm (the first such in the United States), including the use of non-organic fish food; because no such fish food was available. They said it was analogous to the situation that occurs all the time where a soil-based farmer is allowed to use manure on his crops from animals that were NOT fed organically, but the crops are still certified organic. Oregon Tilth has said that "at the time an organic fish food becomes available, we must use it".

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    Where can I buy fish to use for the aquaponics system in my area?

    Good question! I have no idea where you can get fish, not knowing in what part of the country (or even what country for that matter) you live in.

    However, if you have a University nearby, they often have Agriculture Extension Agents. These are people who give farmers advice on what to grow, how to grow it, etc. If you are lucky, the university near you will have an Aquaculture Extension Agent who can give you the same information about fish. They will be able to tell you who is growing fish in your area and suggest sources for you to get fry (baby fish) from. You can also check with any aquaculturists (fish farmers) in your area, as well as local aquarium stores. Also, you can get a wetsuit and a seine net, and go out and net fish out of a local river or lake for use in your aquaponics system (legally, of course, and observing all local regulations and catch limits).

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    Do you have a spreadsheet of cost of production you would share ?

    Yes. We include it as part of our Commercial Aquaponics Group Trainings, Personal Intensive Trainings, and our Do-It-Myself Commercial package sold on our website. Because it only means something in the specific context of the courses we give, and might do more harm than good without the course surrounding it, so to speak, we do not give it away free to the public.

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    I have a couple of questions: 1) What is the tube of polyethylene calk for, and why not use silicone? 2) My site is a concrete slab. Do I need to secure the bottom of the troughs to the ground. The instructions aren't clear on this, but the pictures look like there are stakes in the ground. 3) I may have to get a fish tank built out of galvanized sheet metal (I'm currently in India and don't have access to some of the items you recommend). Do you foresee a problem? Can I caulk with silicone? 4) Can you recommend a way to make the holes in the rafts?

    1. The tube of polyethylene calk is for sealing the bulkhead fittings where they go through tanks and trough liners. We don't use silicone because it was developed to seal quartz windows into aluminum spacecraft, and doesn't still very well, or very long, to anything else. No spacecraft in an aquaponics system!

    2. It's not clear which of our manuals you have, but I'm guessing it's the Micro System, because the others are staked to the ground with concrete form stakes every 8 feet or so. The Micro System troughs are so short (only 8 feet long) they do not need these stakes for support. If you build troughs longer than this 8 foot we suggest you put a form stake every 8 feet or so along both sides. A benefit of this in the Micro System, besides making it cheaper and easier to build, is that the troughs can be emptied of water and easily moved to another location (they only weigh about 50 lbs each when dry).

    3. Galvanized metal ANYWHERE in contact with water in your system is a BAD idea. The zinc is highly toxic both to the fish and plants. Enough said? In India, try a concrete tank that you wash several times with muriatic acid to neutralize the highly basic new concrete, then test pH after filling with water before putting fish in.

    4. You make the holes in the rafts with a simple hole saw, by sawing first from one side as far as you can go, then turning the raft over and finishing the hole (and taking the "plug" of foam out) from the other side.

31. Rating: +0

    

    Since Oregon Tilth certified your system organic you must feed the fish organic fish food. What does the fish food that you use contain and where can I get some?

    Our organic certifying agency, Oregon Tilth, approved our organic certification as an aquaponics farm (the first such in the United States), including the use of non-organic fish food; because no such fish food was available. They said it was analogous to the situation that occurs all the time where a soil-based farmer is allowed to use manure on his crops from animals that were NOT fed organically, but the crops are still certified organic. Oregon Tilth has said that "at the time an organic fish food becomes available, we must use it". At this writing, no organic fish food is currently available in packages larger than the 4 ounces sold at $6.95 from our local aquarium stores, and Tilth has said we must be able to get a "reasonably affordable" organic fish food.

32. Rating: +0

    

    Is a year-around aquaponics farm viable here in the desert near Phoenix, Arizona, or anyplace else with a cold winter climate?

    The short answer is "yes", but the easiest thing you can do first to make cold-weather aquaponics easier is to get a cold-water fish if you can find one that's legal in your state. I've enclosed the section from our manual on cold-weather growing just so you can get a feel for the quality of our information:

    II-A-6. Dealing With Climate: Greenhouses, Fish Houses, and Insulation

    A. Greenhouses: How to understand them and select the right one for you.

    v We're lucky to have our farm in a climate that is pretty hospitable year-round. Even so, we are considering putting in greenhouses for our hydroponics next year after the worst winter in 33 years here. For readers who are not farming in Hawaii, or a similar climate, you may need protection for your crops in the winter, and perhaps even most of the year. This means a greenhouse, and perhaps even heating, if you have a cheap source of heat. How do you tell if you need a greenhouse? Ask the other farmers in your area. If they're growing a produce item in greenhouses, you can too, with the added benefits of your produce being organic, and of raising fish in addition to the vegetables. At the very least, you need to keep your fish alive and well through the winter, even if you don't plan on growing produce year-round.

    v Greenhouses come in a confusing variety of types, shapes, materials, and costs. The cheaper ones let less light through and more heat out. The more expensive ones let more light in and less heat out. When you're selecting a greenhouse, you need to strike a balance between the climate conditions you want inside, and what your budget can stand. Your local trusted greenhouse supplier, or a farmer with a lot of experience with greenhouses, is the person you want to talk to about this. Don't just let a salesperson sell you something.

    The cheapest greenhouse is what's known as a cold frame. These are usually semicircular steel frames with plastic sheeting stretched over the frame. They are easy to erect yourself, and relatively easy and cheap to repair if there is wind or hail damage to the structure. A good example of this kind of greenhouse is Conleys CF Series 1000 Cold Frames (Conley Mfg and Sales, 800-377-8441, www.conleys.com on the Web).

    More expensive greenhouses meet Building Code requirements, often have double- or triple-layer insulated plastic sheeting, either rigid or inflated, for insulation, and often have large venting systems for getting rid of summer heat as well as heating systems for keeping temperatures comfortable for the plants in the winter. Good examples are the Conley's 4000, 5000, and 7500 Series greenhouses.

    B. Fish Houses: (Why would fish need a house? They live in tanks!)

    v The first step you take if your climate is too cold is get a cold-water fish to use in your aquaponics. Trout, yellow perch (and some other perch species), some varieties of catfish, and many other fish thrive in a much lower water temperature range than the tilapia we use in Hawaii. How your find out about what's available in your area is to contact the local University Aquaculture Extension Agent or SeaGrant agent (see VI-C-2. State Extension Agents: Agriculture, Aquaculture, State Fish Vet.) . Tilapia need water temperatures between 70-79 degrees to do well. One way you can get the water warmer, if all you have to use is warm-water fish and you are in a cold climate, is to put the fish in a fish house. What's a fish house? Like a greenhouse, but it isn't green, it's black. A simple fish house would be a 2x4 framed structure with black plastic sheeting tacked to three sides and the roof, with clear plastic tacked over the south-facing side (and a door, of course). The fish house will suck in heat and keep it in. This is the cheapest way to get your fish a little warmer.

    v As we've found with our LD systems, you can stop pumping during the dark hours, when the water would lose the most heat back to the environment. So, set your timer to turn off the circulation pump about an hour to half hour before dark, and keep it off until the sun is well up in the morning. Then the heat that has built up in the system water during the day will stay in the fish tank overnight as much as possible. If the fish tank is insulated, then you lose a minimum of heat overnight and the fish stay happy as possible.

    C. Insulation: How to keep what you've gained

    v If you've gone to the trouble of building greenhouses, fish houses, and maybe heating your system water, you want to hang onto what you've paid for (the heat) as much as possible. You do this with insulation. In order of effectiveness compared to cost, we suggest that you first insulate your fish tank. This can be done with 2" raft material floating on top of the tank, and installed under the tank liner when installing the fish tank. You can also put 2" sheet styrofoam outside the tank, cover it with tightly stretched black plastic, and that will insulate the tank nicely.

    v The next thing to insulate is the hydroponics troughs. When you're building them, install a layer of 2" styrofoam under the liner and between the liner sides and the trough sides. IMPORTANT! This will make the troughs 4" wider, and 2" deeper, than the dimensions shown in the construction drawings, so allow for it when constructing troughs.

    v If you're going to buy a greenhouse, you could try installing the fish tank and trough insulation first, and see what kind of heat conservation you get with them alone, before you spend money on a greenhouse. Then you will have some idea how much more heat the greenhouse needs to conserve. You've done the least expensive, most productive insulation first.

    v Here's how we would do it if we were faced with an inclement weather situation, and wanted to save money. We would try the following, in order of effectiveness compared to cost: First, install a minimum of 2" foam insulation on and under the tanks when installing the fish tank and other tanks; THEN build a black plastic fish house around the tanks and stop pumping at night; THEN insulate the hydroponics troughs; THEN buy and install the best greenhouse we could afford; THEN figure out a way to put cheap heat into the water (lots of options here). If we had the time, we would try these options one at a time, testing water temperatures before and after, until we reached our goal. If you can't afford the time, talk to your greenhouse supplier, look at your budget, and make a good guess.

    v Look at it this way: most farmers in temperate climates ONLY have a 5-month to 7-month long growing season. If you can stretch your growing season even by a month or two with the preceding tactics and methods, you will have a competitive advantage over them. If you grow in even a small greenhouse using high-value crops during the worst of the winter, you will have an even bigger competitive advantage.

    I hope this answers some of your questions. It's doable, it's just a combined equation of your budget, your skills level (how much you can build yourself and how much you need to buy), and your business skills. If ANYONE is growing in your area in a greenhouse, then I guarantee you can do better than them with aquaponics, AND get organically certified, which is worth a lot more on the market than conventionally-farmed produce.

33. Rating: +0

    

    If there is 64 sq ft of grow troughs in a system your formula limits the quantity of fish to 20 lbs. If I built a 700 gal fish tank how many extra fish could I grow without upsetting the stability of the system. I would like to have at least have 40 lbs of fish. What are the negative outcomes from increasing the amount of fish in a system without increasing proportionally the amount of growing troughs? What are the limits?

    First, the size of the fish tank is not what you should be concerned about. Everyone focuses on the fish, because they want protein and/or fish are sexier than plants. We've discovered over the last three years of operation that the fish portion of our farm loses money compared to its operating expenses. When we do an economic comparison with our costs of fish food at $0.90/lb, labor at $12/hr (including benefits), electricity at $0.44/kilowatthour, and using a retail sales price of $5/lb for the fish, we lose quite a bit of money on the fish. If we only get a wholesale price of $2.50/lb (more likely), we lose even MORE money. What this means to a backyard operator is that unless you have almost free electricity and fish food, you will spend more money trying to raise more fish. It would be simpler and cheaper to just buy the fish. But the vegetables! That's another thing entirely; the income from our commercial systems comes 92% from the vegetables and only 8% from the fish. The fish are a great fertilizer generator, and the income from them helps defray some of the expense of having them in the system.

    The reason there is so much focus on the fish is that much of the available aquaculture information in the world mostly comes from universities (NOT successful commercial aquaculturists), which do not have to turn a profit on their operations. Thus they can say they've developed "improved aquaculture techniques" that still stand no chance of success in the real world when they have to pay their own way and make a profit. The real problem is that aquaculture is just a feedlot, like a cattle or chicken operation except with water. The economic equation is very simple and it's consequences inescapable: costs of baby fish, fish food, labor, and electricity in on one side; and whatever you can sell the fish for on the other. Because China and the Asian countries can do this far cheaper than we can, there there is very little economically successful Western aquaculture except marine aquaculture.

    On your questions about proportions in the systems: Our systems are all deep-water culture raft systems, and don't use flood-and-drain, which can create huge (read expensive!) problems in a commercial application of aquaponics. That is why this technology is most commonly used in small backyard systems where costs and productivity don't matter as much. We look at this whole subject of "ratios" differently, and recommend a ratio of 0.3 lbs of fish per square foot of raft area; about 4 gallons of fish tank volume per pound of fish in the fish tank; and 1.5 cubic feet per minute (cfm) of air @ 40" of H2O supplied by your blower for every 100 lbs of fish in a system. This aeration may need to be increased if your water is warmer than our 70-76 degrees F range, as the fish need more oxygen at higher water temperatures, and also because the water "lets go of" oxygen more easily when the temp is high.

    So, in a typical 4,156 square foot "small commercial system" of our design, we will have about 1,200 pounds of fish in a 5,000 gallon fish tank with about 18 to 20 cfm of air @ 40" H2O air pressure being supplied by the blower. This system has 4,156 square feet of grow bed area, or about 30 times the area of the 12' by 12' fish tank that holds all those fish. Aquaponics systems with roughly the same amount of grow bed area as tank area are growing way less vegetables than they could if they were sized properly (assuming they used the above ratios we developed in three years of commercial operating experience).

34. Rating: +0

    

    I want to build as close to 100% self sustainable aquaponics systems as possible. Can you touch on this question, especially alternatives for fish food I can make myself, seed harvesting to avoid having to buy seeds, etc. I am at an aquaponics place that uses air blowers and siphonage for aeration and moving water. Is this more efficient then a pump and blower?

    First, the answer to your first question is in the FAQ question titled "What can I feed tilapia besides commercial fish food?"

    Secondly, we have often thought (and SUGGESTED to our commercial training groups) that an aquaponics farm devoted solely to producing seed for other farming operations would be a KILLER application for aquaponics, since everything grows (AND goes to seed!), in half the time or less that it does in the ground!.

    Thirdly, in the water depths we use in aquaponics, for a commercial-sized system, regenerative air blowers coupled with medium-pore airstones are the most economical way to get air to the fish in terms of electrical consumption. You CAN put together an aeration system that costs a QUARTER as much (to BUY, only) with a regular air compressor and some soaker hose from a hardware store, but your electric bill for the first year will be DOUBLE the cost of the correct system with the regenerative blower PLUS its electricity cost. If you have a small system, getting appropriately-sized air and water pumps from Aquatic EcoSystems (for free catalog call 1-877-347-4788) is the best way to go. Air lift pumps do work (what you're calling "siphonage"), but they're notoriously inefficient in terms of electrical consumption. A low-head, high-volume, energy-efficient water pump is the most economical way to circulate or move water on an aquaponics farm.

    Fourth, we are beginning research into wind and solar-powered pumping and aeration. Not to find out if they work (we know they DO), but to establish baseline costs for using these technologies to see where and under what circumstances they become economically viable, even for small aquaponics operators.

35. Rating: +0

    

    When is your next training?

    Our next training is scheduled for October 4-7, 2010, with a two-day Biogas training following on the 8th and 9th.

36. Rating: +0

    

    Do you offer apprenticeship or internship programs?

    We have an ongoing internship program with between 4 to 8 interns living on the farm at a time. We provide all food (we eat WELL!), decent room with laundry privileges and internet connection, hot showers, etc. The details of this program are on our website on this page (http://www.friendlyaquaponics.com/internships/) In addition to this arrangement, there are other opportunities for paid work from time to time.

    After six months on the farm, you get to attend one of our Commercial Aquaponics Trainings at no charge (value $1,500), complete with all course materials. The interns are our Farmily, and get invited everywhere with us (in our 15-passenger 4WD van). It is a family farm, with four kids from 5 to 14, and so we allow no drugs, drama, drunkenness, intern one-nighters, or other messy behavior. What you do off the farm is your business. We also do not allow ANY tobacco in any form onto the farm, because of the risk of tobacco mosaic virus to our cash crops. If you want to apply for the internship program, simply email Susanne (our personnel manager) at contact@friendlyaquaponics.com.

37. Rating: +0

    

    Where can I get some net pots in large quantities (5,000 pots), and some trough liner?

    You can get the net pots at greenhouse and nursery supply stores. What we use are "Poppelmann" 2" net pots WITH a rim. We accidentally got the Poppelmanns without the rim once; we noticed when they slid right through the holes in the rafts and went underwater!

    Trough liner is ofter referred to as greenhouse cover material. It is 20 to 23 mils thick, is often reinforced with fibers, and is made from LDPE (Low Density PolyEthylene), and is usually found at the same greenhouse and nursery supply stores you can get the net pots at. DO NOT ask for hydroponic trough liner, NO ONE will have any idea what you're talking about. Two kinds of liner we've used successfully are 23-mil P2000 by Inland Plastics Company, and 20-mil DuraSkrim R20WW by Raven Industries.

    Don't use EPDM, a common black rubber pond liner, we have reports of systems taking a LONG time to startup when using this liner for trough liner. It is also NOT food-grade nor organically certifiable.

38. Rating: +0

    

    Have you ever tried growing rice?

    No, but we've grown lots of taro, which grows just like rice in flooded paddies. Taro grows quite well in aquaponics systems, so I would imagine rice would also. However, the goal we haven't achieved YET (on a commercial level) is how to make building and operating an aquaponics system cheap enough so that you can still turn a profit with these types of crops that take a LONG time to grow to harvestable size.

39. Rating: +0

    

    I would like to find a way to set up a semi-aquaculture system which uses aquarium wastewater and other readily available household chemicals as nutrients for a home hydroponics system. This system would be produce leafy vegetables, like spinach, which have recently made news in E.Coli outbreaks. I saw in your FAQ that fish don't produce this bacteria, but want to make sure that in a closed system, aquarium wastewater is free from other pathogens and safe as a fertilizer.

    Aquariums are very different than aquaponics systems; they are set up to keep the water AS CLEAN as possible, whereas aquaponics systems are set up to generate as much nutrients as they can affordably. Aquariums filter out and process all the nutrients possible so that there's as little as possible for algae to grow on. So an operating aquarium is NOT a good place to build an aquaponics system from. You can use an old aquarium TANK however, if it is properly plumbed, aerated, and connected via a water circulation pump to some grow beds or troughs. Aquariums are generally owned by people with disposable income (in the first place) NOT by poor people on food stamps in the city.There ARE cheap ways for low-income individuals to build good-sized functional aquaponics systems out of recycled stuff (such as junk refrigerators, for instance).

40. Rating: +0

    

    We will be moving to an end-of-the-road house soon and living off the grid. Although we raise much of our own food organically but in soil, this will be our first off the grid and aquaponic adventure. How much electricity would one of your systems suitable for a family of 3 require? What size would this system be?

    You could probably raise enough for a family of three and have some spare to trade from a Micro System 64, definitely lots to spare from the Micro System 128. We are putting up these new Micro System plans on the website soon (today's 6-7-10), and they include the current Micro System 64 (64 square feet) which uses 40 watts 24/7, and an expanded version called the Micro System 128 (128 square feet) which uses 48 watts 24/7 but has twice the grow area of the 64!

41. Rating: +0

    

    I live on 5 acres that have clear areas between mostly oak hummocks. I also have a pasture for a cow that I would hate to give up. Can I do aquaponics in the partial shade of trees? Can I build awnings over the system with netting to stop some of the leaf droppings?I have seen systems set up with net covered awnings online, but don't see how the plants get enough light to grow well. What are the light requirements?

    Good question. We found that getting an aquaponics system to grow things well requires good sunshine and lots of it. ANYTHING that cuts the sunlight to your system will reduce its productivity. If you're in a colder climate and have to use a greenhouse to keep your fish and plants warm, you will lose some sunshine. The more a greenhouse costs, the more heat it holds in and the more sunshine it lets in, so this means an expensive greenhouse for maximum productivity. We'd much rather be doing aquaponics in a location that had 365-day sunshine where we had to haul water to the farm and generate our own electricity; than in one that had free water and electricity but poor sun. Even with a commercial farm, we'd make more money this way.

42. Rating: +0

    

    On the Mainland, we have a real potential problem with chlorine in the municipal water supplies as well as other additives. It appears there are wide differences in what is an acceptable "dosage" in various jurisdictions. Do you test for chlorine and other chemicals? Have other people on the Mainland experienced problems with this issue, especially as it relates to fish?

    Chlorine is not an issue in a water supply for aquaponics systems, you simply put the chlorine-containing water in a separate tank and allow it to outgas for a day or so (testing to make sure) before introducing it to your aquaponics system. Chlorine leaves water very quickly if the water is in the sun, and even more so if you have some airstones bubbling air through the water. In practice, if the chlorine levels in your water are low, you can top up the system on a daily or weekly basis without harming production or your fish. When we put a LARGE amount of new water into a system, such as when we initially fill a new system's tanks and troughs, we always let it outgas for a couple of days before introducing fish.

43. Rating: +0

    

    I assume you have water losses due to heat and vapor loss... especially in your hot climate. Are you operating on a private well or through a municipal system? I know you haven't changed out the water but I must assume you have supplemented the tanks with fresh water due to the afore-mentioned loss. Is this replacement considerable throughout the year? Please comment further.

    As best we can tell from monitoring our systems during times of drought, water usage of these systems is VERY low, around 2-5% of what it takes to grow the same crops in the ground. If you have rainfall, your water usage is even less than this, down to zero, because the systems function as their own catchments. It is difficult for us to run an exacting water consumption test for any length of time, because every time it rains we get a "contribution" from the sky. When this happens, we can't tell how much we put in, and how much the rain put in, because the system is overflowing.

44. Rating: +0

    

    What are the distinct differences between the family and the commercial do-it-myself packages?. I'd like to purchase your family/off grid plans, but don't have a mailing address here, can I get it as just a download?

    The Family system is 256 square feet of growing area and the manual is designed to teach you everything we know about aquaponics that you need to know to grow for your family or a small community. It includes plans, drawings, and materials lists for our smaller 64 and 128 square foot Micro Systems as well as its own plans.

    The Commercial system is up to 4,600 square feet of growing area and the manual is designed to teach you everything we know about aquaponics, as well as USDA Organic certification, Food Safety Certification, Health Department certification, value-added processing, marketing, what to grow, how to sell it, what kind of a processing facility you need, water quality, how to build and run a fish hatchery, how to harvest fish, vegetable varieties, greenhouses and cold-weather growing requirements, and much more. It includes plans, drawings, and materials lists for our smaller 64 and 128 square foot Micro Systems, and for the 256 square foot Family system so you can start affordably with one of these smaller systems to gain experience.

    Even our downloadable Micro System manual is up to 24 megabytes in size now, and the Family and Commercial packages filesizes are too HUGE to ever do a download of. In addition, these two packages have CAD drawings on 36-inch by 24-inch sheets, and most people do not have a printer this size. So we continue printing and snail-mailing our larger plans packages to clients.

45. Rating: +0

    

    What about growing tubers such as potatoes? Have you experimented with this? What about rice? It would seem that rice and crawfish would go hand in hand in this system... as this pairing does in ground-based systems in Texas and the South. Comments?

    We've grown a number of weird things such as parsnips, beets, turnips, taro, onions, and kohlrabi; all these rooting plants grow their root bulb up on TOP of the little 2" pots we planted them in, and some of them get really huge. We've gotten three pound turnips and three and a half pound taro roots. If you grow crawfish in your system, that's all you will be growing for ever and ever. They are like piranha with opposing thumbs, and they take WALKS at night across country to other ponds/streams/aquaponics systems nearby and colonize them. They are nearly impossible to get out of an aquaponics system once they're in there. This might work with rice only in the hydroponics, but we haven't tried that yet. Be REALLY careful with crawfish!

46. Rating: +0

    

    How do you control pests on your vegetables, and what medicines you can give to the sick fish?

    We use Bacillis thuringiensis, also known as BT, to control caterpillars. It is sprayed on the plants. When when the caterpillar eats a leaf, it ingests the BT, which liquifies its digestive system. For whiteflies, aphids, thrips and other soft-bodied insects we use BotaniGard, which is the tradename for Beauveria vassiana, a fungus which attacks these insects on contact and feeds on them. Both of these are organic insecticides approved by OMRI (Organic Materials Review Institute), and are also approved for ZERO re-entry time , which means you can spray them on the plant then eat the plant immediately with no harm to the person doing the eating.

    In three years of operation we have never had a single disease incident in our fish. We think this is because of the extremely high water quality in our aquaponics systems. DO (dissolved oxygen) in our systems runs 6.0 ppm or higher, ammonia in the systems runs 0.5 ppm or less, nitrites 0.5 ppm or less, and nitrates 20 ppm or less.

47. Rating: +0

    

    I'm concerned I may need to COOL my water since I live in Tucson, AZ. The ambient air temp. exceeds 95F to 105F in the shade for 6 or 7 hours/day in the summer. Do you have any experience or thoughts about this?

    The mass of water in an aquaponics system keeps the temperatures an average between the nighttime and daytime air temperatures. So what really matters is not what the air temp is in the daytime, but what the average air temp is and what your average water temp is. To check this, fill a 40-gallon trashcan or 55-gallon barrel full of water and monitor its temperature for one week, both summer and winter. If by the end of the day, the water does not get above 80 degrees, you can grow aquaponically with no problems; above 88 degrees F, you can grow OK with minor problems.

48. Rating: +0

    

    Why did you chose a raft system instead of a flood and drain system? (What are the pros and cons?)

    Raft systems do not have the problems with anaerobic zones that gravel bed flood and drain systems do. Also, it is about five times less work to plant into and harvest out of a raft system, where you can remove the rafts and put them on sawhorses to do most of your harvesting at waist level. This really makes a difference labor costs if you're running a commercial aquaponics system.

49. Rating: +0

    

    Hi Can I write a small research paper and submit it as a FAQ question to learn everything I need to know about aquaponics?

    Unfortunately, we don't have the time or the funding necessary to be able to answer FAQ questions with this kind of depth. What we HAVE done is to put everything we know in our DIY Commercial Aquaponics Training. We say "If you need a consultant after you read our material, we haven't done our job". We do a LOT of free support for our clients who either purchase this package or attend one of our live Commercial Trainings, IF they actually go out and build an aquaponics system and start a farm.

50. Rating: +0

    

    In reference to question # 46 and the answer: I found this and was concerned there would be a problem. This is off the label for BotaniGard. "This product may be toxic to fish. Do not apply directly to water, to areas where surface water is present or to intertidal areas below the mean high water mark. Do not contaminate water by cleaning of equipment or disposal of equipment wash waters."

    BotaniGard is an OMRI-approved organic insecticide that is classified as for immediate consumption. This means you can spray the stuff on the plants then immediately eat them with no danger. We have had no problems with Botanigard and no fish fatalities or disease linked to its use on our vegetables.

51. Rating: +0

    

    What is the expected life of the various components in your micro system? For example, the pump, the floating material, etc.

    The pumps usually have a one- to three-year warranty. The styrofoam rafts will last years if you paint them and take care of them.

52. Rating: +0

    

    How can we know if our blower and water pump is just enough for our system?

    You need about 1-1/2 cfm of air at 40" H20 per hundred pounds of fish in your system (in 75 degree F water, MORE in warmer water), and a minimum of 4 gpm flow into each 4' wide by 12" deep hydroponics trough.

53. Rating: +0

    

    Using your ratios, of approximately 20 lbs of fish, will this system provide enough nutrients to grow fruit-bearing vegetables such as tomatoes, cucumbers, onions, etc.? If not, how should I modify your 64 systems...with a larger tank and more fish?

    It grows fruits and vegetables just fine with the standard 20 lbs of fish. You can modify it to 128 square feet with a larger tank and 2X the fish, if you want to grow twice as much.

54. Rating: +0

    

    i want to use solar power for the pumps, is it okay for the plants if the water is circulated til the sun goes down, will the plants be okay

    We have had systems operate successfully only pumping during daytime hours. The only thing you need to make sure of is that your fish still have plenty of oxygen during the pump's off periods. They still need to breathe even at night.

55. Rating: +0

    

    I would like more information about your commercial aquaponics plans. How large of an area does it cover, what are the construction costs, & what is the projected income from each one? We are looking to sell our business & build a hydroponics farm in the next 6-12 months.

    This is a difficult question to answer, because prices are locale-sensitive, and there is a huge difference in potential income between a system growing cabbage and one growing strawberries, for example. There are two "standard" systems of 1,024 and 4,096 square feet in the plans, and information on how to scale systems to any size you wish, including information on how to size blowers, pumps, and air and water lines appropriately. We have about 5,400 square feet of growing area, plus the processing facility for that, the walkin fridge, 1,200 square feet of sprouting tables, planting shed, tilapia breeding tanks, and some other stuff in about 20,000 square feet of total area. We are grossing about $150,000 a year on this now, at Hawaii prices (but paying Hawaii prices for expenses also!).

56. Rating: +0

    

    We started up a smaller system and have lettuce growing, but now we have tiny flies on the lettuce and they are laying black eggs. I don't know if they are fruit flies or some other fly any ideas? will BotaniGard work on those flies, where can i get some on island? how often do you treat? thanks

    Go to your local University Ag Extension agent with a sample of the fly; she will tell you what it is, and what kind of organic pest controls you can use for it. If it is a fruit fly of some kind, you can hang baits in plastic jugs around the vegetables and the flies will go in there to be trapped and die.

57. Rating: +0

    

    looking for a liner to line my organic grow beds. What do you recommend?

58. Rating: +0

    

    Have you tried growing quinoa as a food for humans and fish? It is chock full of protein.

    No, but we successfully grew Amaranth, which is a very similar grain.

59. Rating: +0

    

    How do you handle the pumps and aerators when the electricity goes off? Do you use a generator? If so, what sizes do you recommend?

    In our commercial systems we have a backup generator in case of power failure (situated crosswind from the air intakes on the blowers, of course!), and this is what you would want in a system of any size. You need to size this to the electrical load of your particular blower(s) and pump(s). A small aerator with a small inverter and battery would work for a system under 100 square feet.

60. Rating: +0

    

    Is it important to protect the crop and/or fish from rain water? I am guessing the rain water would affect the pH balance or Nitrogen cycle?

    No. The rain does not dilute the system nutrients to the point it affects vegetable growth, even when we had 60 inches of rainfall in 2-1/2 months one year. The pH balance is so stable it is not affected either.

61. Rating: +0

    

    When you say that aquaponics grows "food" -- as opposed to marijuana -- does that mean that the system won't work for violets and other houseplants? I would like to grow flowers - NOT marijuana -- inside, but have very limited space. Eventually, when I'm comfortable with aquaponics, I'd like to grow veggies, but I want to start out with flowers . . . .

    We had many varieties of both ornamental and edible flowers in our first aquaponics test planting, and they all did VERY well! There is a lady on our island earning $1,800 a month from a 12-foot by 20-foot plot of edible flowers in her backyard that she sells to restaurants and hotels. Marijuana is one of the very few things we've heard of that DON't grow well in these systems.

62. Rating: +0

    

    Do I have to use Dow blue board for the rafts? I was thinking of using 2" styrofoam that I can get at HD. Why do you paint the rafts and what type of paint do you use?

    We use 2" Dow Blue Board styrofoam "Square Edge" rafts for our aquaponics, and have had NO problems with them. We paint all our rafts on the top ONLY with two or three coats of a good semigloss white exterior latex enamel. This Blue Board comes in several OTHER configurations which do not work as well: one is called "Tongue and Groove" Blue Board, this is OK, but has a bump on one edge and a groove on the other which make them difficult to paint and also make the edges of the rafts more vulnerable to damage. Another type of Blue Board is called "ScoreBoard", and this one is a pain because it has three scores down the long 8' dimension of the sheet that are designed to help the sheet BREAK EASILY along these scores. It works: they DO break easily along these scores, when you are harvesting, planting, or just looking at them crossways. DON't get "Score Board" unless you have no other choice!

    White Styrofoam such as cheap coolers are made from is OK for rafts, if you don't mind them being VERY easy to damage, not having a long lifetime, and soaking up a small amount of water. They are probably OK for the smaller Apartment/Condo systems, but we wouldn't use them for Micro Systems or anything larger than that.

    IMPORTANT! ALSO DO NOT use pink or white Polyisocyanate foam rafts if you find them. These are often available the same places the Blue Board is, and are cheaper. Does "cyanate" sound like "cyanide" to you? It is a related chemical compound and it is toxic; we have a report of one aquaponicist using it, and although his fish had been fine in the system for a month or so, approximately one-tenth of his fish died the week after he put the rafts in the system. We don't know if the rafts were causal here, do you want to experiment and find out?

63. Rating: +0

    

    Real businesses have a real merchant account and don't lose business or orders due to the difficulties of using Paypal. Are you planning on getting a merchant account in the future?

    We are a "real sustainable business", which means we consciously operate in such a manner as to reduce costs to our customers whenever possible. "Real" merchant accounts take up to 4% of all transactions (which requires us to charge OUR customers more to keep up); require a high level of credit-worthiness we don't exhibit right now (having fought our way back from a near-bankruptcy two years ago); and KEEP A CONTINUAL 30% AVERAGE of all funds passed through the account so they have a "cushion" in case you have back-charges or customer issues. All this costs us more money, and means we would have to charge our customers more simply to supply them with the same products and services.

64. Rating: +0

    

    Have you or any of your students built a roof-top aquaponics system? Do you see any problems with this?

    We have some students at a homeless shelter in LA building one now. The considerations are these: 1. Weight of the water. It weighs 64 lbs per cubic foot, and roofs are often NOT built to carry heavy loads. 2. Cooling. If you put shallow hydroponics troughs on a roof to save weight, they will suck in heat faster, heat up the water and stunt of kill the plants. You can get around this by putting a large fish tank on the ground floor or a lower floor that can carry its weight, then pumping the cool water from it through your shallow (and light) growbeds on the roof at a sufficient rate to keep the plants cool through the new cool water coming in. Other than that, rooftop aquaponics is a GREAT idea!

65. Rating: +0

    

    My system is ready and I would like to start fishless cycling. I will be buying pure ammonia.I don't know anyone else with a system nearby that I can get water from to add some good bacteria to mine.How much ammonia should I add (approx 4,000 gal total water in system) and should I be adding anything else to it as well?

    You can't buy "pure" ammonia as it is a legally regulated, highly caustic gas/liquid depending on what pressure and temperature it is stored at. If you want to start your system, just put a 1/4 cup of household ammonia with NO detergent (!!!) into your fish tank for each 100 gallons or so of fish tank water; THEN add your nitrifying bacteria (Aquatic EcoSystems catalog #90210, 1-877-347-4788)

66. Rating: +0

    

    Do the plants nearest to where the water from the fish tank enters the troughs grow better than those where it returns into the fish tank? I wonder if the nutrients need to be spread out better. Or is this just added work with no real benefit?

    This is a GOOD question. What you are really asking is if the nutrients in the system water become depleted during their trip through the hydroponics troughs. The answer is: "If they do, we haven't been able to measure it in a single trough in one of our systems that is 300 feet long". We designed this 300-foot long system specifically to test out a theory of ours, namely, that the soluble, measurable nutrient levels in a deepwater aquaponics system are pretty much the same throughout, regardless of where in the system they are measured. What we HAVE noted, though, is that although the nutrients are steady throughout the trough, the DO levels in these long troughs drop the further away from the inflow you get, and so need to be supplemented with additional airstones in the troughs. Our experience seems to indicate that an ideal DO in the troughs is 6 ppm, a good DO is 5 ppm, and an acceptable (but improvable) DO is 4ppm.

67. Rating: +0

    

    Aloha, Have you ever tried using edible climbing vines for natural shade over plants or fish tanks. I am interested in growing more food with very limited space. I am also in a tropical area so water temperature will be challenging. Specifically I am seeking any information on lilikoi, peas, grapes, kiwi other aerial or trellis crops etc. Mahalo

    Peas, climbing beans, and so on grow great in aquaponics systems. A friend of ours tried a lilikoi in his system and it took off like a rocket. We don't have any information on grapes or kiwis, why don't you try them and report back?

68. Rating: +0

    

    Is there anyway that is safe for both the fish and plants to get the water in the fish tank clear so people can actually see into the water to see the fish?

    If your priority is to see the fish, you need to get a freshwater aquarium and forget about aquaponics. The bacteria that are an integral, inseparable part of an aquaponic system render the system water a nice tan tea color. It's fairly clear, just colored. We've tried putting windows in the tanks, and it's disappointing because mostly what you see is just an occasional fish tail. THEY can see you through the window too, and you're a PREDATOR, so they tend to stay away from the window unless they're REALLY crowded in the fish tank.

69. Rating: +0

    

    I purchased the 2010 Micro System DIY plans. I am having problems finding a 20 mil LDPE liner for the troughs. Homedepot has the liners but they are PVC. Will this work? Do you recommend any places that carry this material?

    The PVC that Home Depot carries works fine. DON't use the EPDM they sell, it's toxic! You can try going to a greenhouse supply company and asking for "greenhouse cover material". This is the 20-mil stuff we talk about, it also comes in 12-mil, but that seems a little light to us.

70. Rating: +0

    

    HI correct me if I'm wrong but it seems you dont use multiple tank systems as in UVI for your commercial systems.I'm concerned about trauma caused to fish during harvesting some of the fish, as well as stocking small fish with big fish, the competition for food, and mortality.Could you give me your reason for going with large single tank systems.

    Our first systems to get certified organic were systems with a single fish tank, a solids settling tank, a net tank, and a degas tan These technically were multiple-tank systems, but I think you're asking about multiple FISH tank systems; these were just like UVI's, but with cost-saving innovations of our own in construction and operation. We recently got re-certified by Organic Certifiers of California for these original systems and newer systems that only have a single fish tank and hydroponics troughs (NO other tanks in the system).

    The question you are asking is properly answered by a paper by Dr. Stephen Summerfelt (of the well-known Freshwater Institute on the East Coast), titled "Summerfelt et al. 1993. continuous culture & selective harvest. Techniques for Modern Aquaculture, p 581-595.PDF" This is a paper on CMSGH (Continuous Mixed Stocking, Graded Harvesting), which explains how you can raise double the amount of fish (or more) in a single tank with a special easy-to-use stocking and harvesting method. We have been using this system on our farm for three years now, and have experienced no problems whatsoever with it. We have NO mortalities associated with harvesting the fish, and as long as you feed the tank enough food, there is NO competition for food; the smaller fish simply wait until the bigger ones are full before they come up to eat. We need fewer tanks, we can harvest any amount of fish anytime we want (we don't have to harvest a WHOLE tank when we harvest the way the UVI system has to). The size-grading harvester we built out of $50 worth of PVC pipe and plastic mesh works like a dream: we only spend about ten minutes getting 300 lbs of fish into a cooler.

71. Rating: +0

    

    Comparing to normal soil farming, how much more veggie production can be achieved in the same size area from aquaponics system?

    We experience vegetable maturity in half the time or less that the same vegetable takes in soil; and we can plant four to five times as densely as one can in soil because our nutrients do not get depleted by a crop, but rather are constantly flowing past the vegetable roots and being replenished in the fish tank.