Short version: How long does it take to really neutralize the chlorine in my tapwater, such that it won't kill off any beneficial bacteria when I add it back in to the tank? Long version: When I do water changes, I usually have the water sit out overnight. I still use a dechlorinator (API water conditioner). But when I don't get the chance to use aged water and I have to use fresh tapwater, I add the water conditioner just before and get a little paranoid that some chlorine is getting through just because it hasn't mixed well enough. I know that this and other products love the word "instant" in terms of how safe it makes the water for the fish, but it I just want to get feedback on what other people feel is safe for the bacteria, not just the fish. Also, FYI, I don't do large water changes, usually only a gallon or two at a time (for a 10g tank). So I swirl the water and bubble/agitate it pretty thoroughly (I think) with a turkey baster once I put in the drops of dechlorinator. Should I still be worried that any chlorine is getting through and possibly killing off the bacteria?