I started off just using two UTH's. My humidity would stay at around 60-70%. I added a small CHE just to bump my ambient temps a little and within 24 hours my humidity was down to 30%. I was surprised how much even a small one will dry out a tank. When my BP gets ready to shed I will turn the CHE off fir a couple days and can keep the humidity around 70%. When I am using the CHE I have to spray it once a day to keep it around 45-50%. When mine gets bigger I plan to go toe a pvc with RHP.