humidity is a proble for leopard geckos, they are native to pakistan and india, They live in the dry regions of these countries. I used to keep leopard geckos you might want to up the size of your tank, Males get well over 9 inches in length and a 10g is far to small. You shouldnt need to add humidity unless, you have problems when it sheds. Commonly the toes dont shed all the way. You can solve this with a coolwhip container with a small hole cut in the top with peat moss or vermiculite. also serves are a nest if you would ever get a pair and wish to breed them.