I have been getting low all reading on the tank. 7.1, 7.3, 6.8. Doing weekly 10 gallon water changes. Just tested fresh batch of saltwater dkh 6.8 so I think it may e mixing low (Aquavitro Salinity). Just picked up Seachem Fusion 1&2 to try to raise the all. I saw the brs calculator but for the...