I never get a true yellow 0 Ammonia reading (API liquid kit) out of any of my 3 tanks. It reads about .1-.2, always a bit more yellow than .25 but definitely still a bit of green. Aside from a tank where I experienced an outbreak of fin rot with nipped guppies, the fish and shrimp are all doing well and spawning/breeding. Could this low level ammonia in all tanks reading be caused by chloramine in the tap water that is broken down into Ammonium? And is this a cause for concern? Thanks for any advice!!