Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
The formula for KH is linear. That is, multiply it out, divide it whatever you need to do, and the same ratio will raise the KH the same amount.
1 tsp/30 gallons (actually it was a 29 gallon tank + canister) = 2 degrees KH. When the pH in this (and other tanks) was below 6 (took lab equipment to determine it was 5.8) the pH came up to 6.2.
Same recipe in tanks from 10 gallon to 88 gallon shows the same effect on the KH.
pH is a bit variable, depending on what else is in the tank, but does rise a bit.
1/3 tsp in the 10 gallon = 2dKH
1 scant tablespoon in the 88= 2dKH
If you already have fish in the tank, then I would do these increases slowly, a degree or two every few days so the fish can adapt to it.
If you keep the coral sand, oyster shell grit, dolomite sand, limestone sand, aragonite or other material in a nylon stocking in the filter then you can easily remove it if it is not doing what you want. It is slow acting, so you will have plenty of warning if it is sending the parameters too high.
Prep the water for a water change ahead of time and run a pump to make sure the Equilibrium is well dissolved.