Some keepers won't even use stones in their shrimp tanks, but you will be fine using inert stones.
Simply do a vinegar test or sit your stone in a tub of tap water for a couple days and test it to see what it does to your water before adding it to your tank.
I like to use rocks that will raise the kH (and naturally pH), some good ones are Seiryu, Limestone, and dead Coral. Just be sure what you're introducing is affecting your parameters the way you want it to. Personally I find that if you want to buffer your water you'll be better off using products designed by high-end shrimp keeping companies like Borneo or Mosura. It's much easier to control.
I myself use crushed corals in the filter/refugiums to raise the kH in my shrimp tanks.
Last edited by AVN; 11-05-2012 at 08:20 PM.