Sand is no good. Some people like it as part of a mixture, but I don't. It can cause problems when it gets in their eyes. It can cause impactions if they swallow too much of it and you need to keep the on a substrate that can be kept damp for humidity and sand won't work for that.
Coco coir works great. That's what my hatchlings are on right now. Other's like Cypress mulch, orchid bark, plain soil (if you can even find it) and sphagnum moss. Any of these will work.
While I'm at it, did anyone mention that they need a humid hide box, daily soaks and a good shell spraying 3-4 times a day?
If you do these things they will stay as smooth as they are right now.
