I forgot that I posted that question. Still have not gotten an answer to that question. I am thinking about looking up bonsai nursery's and see if they have any sort of rock that would work.
I just recently read that the igwamui traditional rock raised ph and GH and if one is keeping shrimp that is not always desirable. I might look into lava rock or lace rock which is supposed to be inert in that regard and according to a recent article in tropical fish magazine written by Amano using alternative rock like lava rock is an acceptable choice.
Good luck to us both in finding these rocks.