It's really hard to say with this information. We don't know what kit your using and dark green is kinda subjective. In any case, i'd recommend using RO water instead of what you're currently using to lower your ph. It's really hard to keep your ph stable when you are using chemicals to alter it, and a fluctuating ph is hard on fish. I've found that RO water is a dependable and natural way of lowering my ph.