I have a 20 gallon aquarium that has housed shrimp in the past, I wanted to get OEBT and am aiming for a PH of around 7.0, However my tap water is hard with a PH of 8.0 and even after running it through My RO it still has a Ph of 8. I use Ph neutral regulator by seachem to bring it down to 7.6 I wanted to know if any one knew how to safely lower it further and maintain that pH when doing water changes.