I like to use fine sand (Repti Sand, Jurassic Sand). I have also used play sand, without any problems. Contrary to what many individuals believe, you only need 1/2-1" of sand as long as you make sure that the sand is moist under a hide or in a small area of the enclosure. P. rangei are completely fine without 4+" of sand. When you have such a layer of sand, it becomes difficult to locate eggs in the enclosure. Also, my breeders, and juveniles for that matter, are able to dig tunnels in the moist area.