I have a humidity problem with my ball python set up it fluctuates between 40 and 80%, but stays around 40 most of the time. I have a 20 gallon glass terrarium. I first bought a uth for a 10-20 gallon tank, but it wont heat it sufficiently. SO I got a heat light as well now my temp is perfect. I also cover the top screen with a towel to try to keep the humidity in. I mist the tank a couple times a day. This only helps for a little bit. I also have aspen bedding to help with the humidity. Any suggestions on how to keep the humidity up. Oh yeah I also have a large water bowl filled with water.