I have a 25 gallon tank that I have mine in and humm and temps were a pain to control. I added a second UTH, attatched styrofoam isolation to the out side of the back and 3 of the sides, topped the mesh top with syrofam as well and cut an opening for the lamp that i rarelly use unless the room is gonna be cold. I have both of the UTH's running on dimmers and the temps are moniters regularly and I have had consistant 88-90 hot sides and 79-82 cool side with 60-70% humm. There is also a small opening on the otherside that I keep covered with a damp rag.