Please, and I am very sorry to bring bad news, get rid of that one even faster, calci sand is sand that incourages geckos to eat it, it is worse than sand, the problem with loose substrates is the risk of impaction, I would HIGHLY recomend to put them in paper towels, or, if you want to go with a more naturalistic look you can use slate or ceramic tiles, they are very easy to clean, give a nice natural look and are super safe for your geckos´ health!
My only intention is to try and give good advice in the best interest of your geckos, you can search in this very forum there are many cases of sand impaction, and calcisand (no matter how thin) is a product that should be taken out of the market.