What kind of sand should I use for my leopard gecko?

I want to get slate tile for my gecko but Im kinda worried about the sand I have to use to fill the gaps. i used to be a dumb gecko owner and had my gecko housed on sand. The sand smelt soooo bad. My entire room smelt terrible. And that was the very fine sand that should be used if a leopard gecko is put on sand. I wanted to get calcium sand because its bigger and probably wont be as dust and smelly. The problem with that tho is if consumbed in a large enough quantity it can cause impaction. But because Im going to use it as a filler and not as the main substrate I figured the risk of impaction is minimal. What do you gets think?