Before adding CO2 to my brackish water tank the pH would be around 7.6 but with CO2 it is closer to a pH of 6.4 or so. The dKH is 4 and SG is 1.005; plants seam fine, fish (BBG's and guppies) seam fine. What concerns me is the number of times I have read that a pH this low is a problem. Even though I see evidence to the contrary. What can I say that would address this issue? I have a 10 gallon tank. I know the change in pH from CO2 enriched fresh water tanks is not an issue (forgot why ) - is it the same for brackishwater tanks?