I would get two rheostats, or dimmers. Aslo two therms. One to control the output of the UTH and one to control the output of the above tank light if you will be using one of those. If you havent already bought your dome fixture, you can find one with a dimmer built in. With an UTH and a heat source above, your cool end should be fine. Place the above tank light over towards the end with the UTH, and once you have your top covered, the temps on the cool side will be fine.