My geckos tank ok?

Hi there, I wanted to double check that my enclosures sound alright! My animals are important to me and I appreciate any concerns, tips, or suggestions. I have two leopard geckos, Echo and Whisper. I used to keep them together in a 20 gallon long but I noticed that Whisper was not growing and was getting increasingly mean. I finally saw Echo nip him and decided to separate them. Echo is a male and Whisper may be as well but I am not sure. Whisper has become WAY more docile since getting his own cage. Now Echo is in a 20 long with tile as the substrate. The warm side has a cave and a litter box (small box with some sand that he poops in) and the cool side has a cave and a humid hide. I also have a water dish and a cap of calcium powder in there. I just realized the heat is not quite high enough and am working to adjust it, but other than that does the setup sound ok? Whisper's tank is the same except it has paper towel instead of tile and no litter box currently. Thanks!

Yep, sounds like a good, basic setup. Some people are really anti-sand, but as long as you aren't putting something like calcium sand in there, I don't think it will cause a problem. Just remember to change the sand out every once in a while so it doesn't get smelly. Make sure the warm side floor surface gets up around 90 F in each cage, and you'll be all set.