The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
I've got a couple of pieces of limestone fossil conglomerate in my tank. I've also seen a sight from a fellow in Texas who sells "Texas Hole - y Rock" for aquariums. Being from Tx originally, Iv'e got some of this, too. It is in my daughter's 10gal.