Hello all. Once again I find my self seeking to pick your well endowed brains. I had been using repti-sand for my uromastyx and for my leopard geckos. No they are not housed together. Then after hearing the horrors of impaction I went to the repti-carpet. While it is safer, The "Kids" do not like it. They sure are not as active and don't seem to like it at all. so i have decided to go with clay. But as I know slightly more about clay Substrate then I do about astrophysics. I figured I would ask the right people. I have a 75 gal and 40 gal tank. So here are the Questions What is it, How do I use it, Where do I get it, When does it need to be changed? Remember its for my little one so please don't blame them for their dad stupidity. As alway thanks for any info.