Calci sand is bad stuff.

Working with leopard geckos for a while now I have seen first hand what that stuff can do.

Not only does it cause impaction it can also dye the leopard geckos belly and feet the color of the sand.

It is made for them to eat. It's not digestable though. Think about it this way, what happens when you pour water on pure calcium and let it sit? It hardens like a rock. Now imagine that in a leopard geckos stomach? Or other lizards.

Fine clean sifted play sand is safer, I would not use it though just because of the risk. There are safer methods.

In my opinion no I would not recommend it. If it means making sales for the store, recommend reptile carpet.