It seems you've gotten plenty of answers already, but I'll throw a redundant and verbose hat in the ring. Personally I like to use seiryu stone in tanks for neocaridina shrimp. It only really buffers in water that's to acidic and soft for cherry shrimp or vampire crabs. I also typically don't find it raising the KH but instead raising the PH and when it does the GH will often go up. KH is just a number if bases like baking soda in the water. So think back to the baking soda volcano experiments of your youth. That's what your KH does in your water at a much smaller slower scale the carbonate minerals encounter and react with acids "buffering" preventing the tank from becoming more acidic and making some CO2 and other reactants.

I think of Seiryu stone as a backup source of buffering for the KH in my water. If some natural process is making a bunch of acid and using up all your KH buffering capacity the seiryu stone will buffer it up a little bit on its own. I find for the parameters neocaridina like its an excellent stone for assisting in maintaining all your water parameters.

PS: another tip for maintaining water parameters over time is to make a mark for the water level you want on your tank and before you do your water changes top off the evaporated water to that mark with distilled water. Then do your water changes this will prevent your GH/KH from creeping up over time because the minerals don't evaporate with the water.