Source Water For Your Aquaponics: City Water
Chlorinated city water is potable water by definition. It is relatively expensive, but you can safely use it for washing babies and drinking. Even filling up a big commercial aquaponics system for the first time only uses ten or twenty dollars worth of our chlorinated “city” water at current prices.
However, you want to be careful of adding large amounts of this (chlorinated) water to a system that has fish or vegetables or both in it. If your water tests positive for chlorine, you should put it in a separate “makeup” water tank for a day or two to burn off the chlorine before putting it in the system. We put 50 to 100 gallons a day of chlorinated water into our systems with no ill effect, as our chlorine level is low or unmeasurable. Measure your chlorine levels with test strips to be sure there is none before putting it directly into your system.
IMPORTANT! You must use a “total chlorine” test to test for chloramines (NH2CL) in your “city” water. A simple “chlorine-only” test will not show the presence of chloramine; you can’t smell it like you can smell chlorine, and so you must use chloramine test strips to tell whether or not you have chloramines in your water. Chloramine is increasingly being used to chlorinate water because it is less expensive, and does not dissipate as quickly as chlorine. Get test strips that test for “total” chlorine, then you will know if you might have chloramine.
When testing for chloramines, make sure your test kit tests for “total chlorine” or “combined chlorine” or for “chloramine and chlorine”, not just for “free chlorine”. A test for “free chlorine” would misleadingly read zero in chloraminated water. You can buy a swimming pool test kit which tests for both chloramine and chlorine, which is the same but usually far less expensive than aquarium test kits. Chloramine is caustic: there are lawsuits all over Southern California from builders who had to replace all the piping in subdivisions they’d built because chloramines had eaten pinholes in the copper pipe they’d used.
Here’s a trick to use to determine if you have chloramine in your city water: If you can’t find “Total Chlorine” test strips, and you have ammonia test strips: test for ammonia. If you see ammonia levels of 0.5 to 3 ppm in water that shows “no” chlorine (when tested with a “chlorine-only test strip), you can be almost certain that your incoming city water has chloramines in it. This is because the ammonia strip responds to the “‘amine” portion of the chloramine, and presents a positive ammonia reading, making it look like you have high ammonia levels in your system. You don’t; you simply need to get a “total chlorine” test strip and try again.
Chloramine does not out-gas as chlorine will with aeration and sunlight, so you have to actively remove it from your water, or wait days or weeks for it to dissipate on its own.
Here’s what we recommend for active removal, if you find that you have chloramine in your water: Many sources cite ascorbic acid(Vitamin C) as a neutralizing agent for chloramine (see Wikipedia article here: http://en.wikipedia.org/wiki/Chloramine). Here’s a source for the NSF-certified chemical (National Sanitation Foundation certification) in quantity from the Integra Chemical Company: http://www.vita-d-chlor.com/index.htm).
Do not use the “Vita-D-Chlor Neutral”, as it is sodium ascorbate. The sodium atom in this compound will break away in water, and recombine with a free chlorine atom to form sodium chloride, AKA salt; that’s bad for your plants!
Do use the “Vita-D-Chlor Granular”; it is ascorbic acid, and will neutralize chloramines if used according to their instructions for concentration and then mixed with your system water (or makeup water).You can neutralize all the chloramine in your system water easily with a one-time application of ascorbic acid when you start up your system, then simply wait two days before you add bacteria and fish for the ascorbic acid will neutralize all by itself (test for chloramines to make sure you’re done!).
After you initially fill and dechloraminate your system,and are now operating a “live” aquaponics system, you will need to add water at irregular intervals to “make up” for water usage. Normally you would fill your “makeup water tank” with tap water, mix in ascorbic acid, and wait a couple of days for the ascorbic acid to self-neutralize. Yes, you need a separate tank for this if your water has chloramines in it, because you cannot put either chloraminated water or ascorbic acid into your live aquaponics system! If you can’t wait several days to a week for the chloramine to self-neutralize before adding the makeup water to your system, you can neutralize the ascorbic acid in the makeup water tank. Wait for three or four hours after adding and mixing in the ascorbic acid, so it has a chance to neutralize the chloramine, then put a couple handfuls of calcium carbonate in with the new water and stir it around thoroughly, and you should be able to safely add the water to your system within three to four hours afterwards. Calcium carbonate is safe: it is coral sand or crushed oyster shell, which we use in our systems anyway to balance pH.
Why do you need to neutralize the ascorbic acid if you’re going to add the water right away? Because ascorbic acid acts as an herbicide in your system; it will sicken or kill the plants and turn their roots black if you add water with high enough quantities in it.
Some of our students say they have successfully used Kordon AmQuel® Ammonia/ Chloramine Remover in their Micro Systems. Proceed carefully with this kind of product, as water conditioners made for aquarium use (as the Kordon product is) do not have certification for use in a food production system. We do not recommend their use.
IMPORTANT! (As If That Wasn’t Enough!) Instead of Chlorine or Chloramine, Some Water Systems now use Bromine to sanitize their water! You should check with your water department to make certain exactly what they’re using to sanitize your potable water, and also check with them on the best way to de-brominate it, if you find that yours uses bromine. Bromine is toxic, just as chlorine and chloramines are, or else it wouldn’t be able to kill the microorganisms in water that it is designed to get rid of. This means it is also toxic to you, your fish, and plants, even though it may be a small amount and only slightly
You can get Sodium Bromide test strips from pool and spa stores to find out if you have it in your water. The US Navy uses up to 1 ppm of bromine to purify their water aboard ships; this bromine then breaks down into bromides in the water and in the human body. Bromides are used in quantities far greater than this for anti-epileptic, sedative, and diuretic drugs for human use, and are approved for this use by the FDA. However, because of the sketchy information available on bromines in water, you need to find out if yours has it, and then make your own determination on it’s safety to use in your aquaponics system, we can’t tell you yes or no!
WARNING: For Chloramine And Bromine-Purified Water! If you are planning to sell organically certified produce from a commercial scale operation, make certain your organic certification agency will allow use of water purified with chloramines or bromines, and then removed with whatever your chosen method of removing them is, before you literally buy the farm, and get it in writing! We have been certified USDA organic by two separate large certification agencies with plain chlorinated water used to fill and top up our systems; we don’t know if they’ll approve the use of chloraminated or brominated water.