So I have a 40 gallon tank for my BP. Currently, I have an UTH (a medium size I believe) on one side, and a heat bulb up top. I want the opposite side to be warmer at night, as I think she's been staying under her log because it might be too cold for her. I really don't need something huge, just enough to raise it a couple degrees. So, should I get a mini size, meant for a 10gal tank, or a small (10-20gal)? If I get a second UTH, do I even need the bulb at all since it dries out the tank a lot?
Also, is it better to put the UTH under the tank or on the side? I had one on the bottom of my old tank and it got ridiculously hot. When I put it one the side, it gave a more even spread of heat.