Thank you, I’ve heard so many mixed reviews on this type or that type. He’s on slate now with crushed walnuts to fill the gaps. Still not sure what works best.We use a disinfectant called F10 and clean ours out every couple of months. This was the disinfect recommended by a specialist exotic animal vet. As for substrate we use the eco earth type substrate which was also recommended to us. It’s apparently safe for use with leopard geckos. I’ve had the same set up for 13 years and haven’t had any issues, my geckos are getting old now! We also use moss inside hides for them to help keep humidity up.