It takes a tablespoon of GH booster in 20 gallons of water to raise the GH by 2 degrees. A quarter teaspoon would only raise it 1/12 th as much or about .17 degrees. You need to add a lot more.

KH measured by our KH kits is a measurement of alkalinity, which would be carbonates if the water contained only those anions in large quantities. Calcium carbonate is the usual substance in water that gives both GH (calcium) and KH (carbonates), so we usually see both KH and GH being high or low together. But, obviously, there can be other things in the water that contribute to alkalinity.

I think I am right about this. If not, I hope someone will correct it.