In this pic, we see a comparison of the chlorine level between DC tap water and from an aquaponic system with the same source water. Five months ago this 30-gallon aquaponic system was treated with a small bottlecap-full of a solution to remove chloramine (“total chlorine”). Despite frequent top-offs from the same tap, there is still no chloramine detected in the aquaponic system, whereas the tapwater has 3ppm.
Municipalities add chlorine and sometimes chloramine to disinfect public drinking water. The DC Water website states: “The drinking water delivered by DC Water contains chloramines.”
Chlorine (“free chlorine”) will off-gas and dissipate naturally. But chloramine (“total chlorine”) needs to be actively removed.
Unfortunately, the same chlorine and chloramine that keeps our drinking water safe can kill our aquaponic “biofilter”: the large bacterial colony that converts fish waste into plantfood. So check with your municipality and address your chloramines if necessary so you dont kill your bacteria and your fish don’t choke on their own toxic ammonia. 🙂