I spent a great deal of time and energy reading about sand substrate and the controversies behind it, and I wish now that I listened! I just came home from the Exotic Animal Vet and after $200+ the vet told me that my Leopard Gecko Leo had impacted sand inside of her, which is why she could not go to the bathroom, eat, move around normally, and she lost her vibrant colors. This can all easily be avoided by using paper towels or terrarium carpet. Unfortunately, the packaging of the T-Rex Bone Aid Sand Substrate read, "Beneficial to Eat"... read full review »