I use a 40-gallon glass tank for my adult male. As long as you wipe it down every week or so, it is very transparent. If you're just using the basic heat pad plus light combo then any T-stat you are using right now should be OK. For my glass tanks, I like to saturate my substrate on a weekly basis and allow it dry throughout the week, my screen is unblocked. One thing to keep in mind though, is the more stuff you have in the cage, the more cleaning you have to do so it pays to have some nice front opening doors like those on AP cages...I love my 40-gallon, but having to reach in from the top every cleaning day does get a bit inconvenient.