Have you run any water quality tests on it? Ammonia, Nitrates, pH?
Negative. I'll have to check it out. Rain water does most of the filling, but I do add some tap water on occasion depending how dry it's been. I'll use a little De-chlorinater and some barley extract when needed. I only feed them about every other day just in case mosquitoes take up residence. I clean the filter on the pump about once a week.