I am using a thermostat (repti500). I decreased the temps down to low 90's on hot side. I plan to switch him to a smaller enclosure after he digests his meal from last night (15qt). The problem I have with the larger enclosure, which I am wondering what will happen when I eventually do transfer him back into the large tub, is that I feel like I might have to use an additional heat source. My house stays around 68-70 degrees and I cant get the other side of the larger tub above 75. I am sure it would be easier when I transfer him into the smaller tub for the moment. Dont most people use just a UTH for a tub? I am using the larger UTH from zoo med and have read its best to cover around 1/3 of the tub (which is about right in my case).