I use one teaspoon of marine salt mix, one teaspoon of baking soda, and one tablespoon of Epsom salt per 20 gallons in all of my tanks and pond to raise KH and keep pH elevated and steady, including my GT's tank.
However, I do not use "aquarium salt," which many hobbyists feel the need to dump into their tanks at an alarming rate, with no real reason for doing so. Some feel it helps the fish, but I've never really understood why.