Hello everyone. I am currently trying to properly set up a 20 gallon terriarium for my newly purchased Leopard Geckos. I have a overhead heating lamp that I keep on during the day, and then shut off in the evening. I have also read that they need one area to be even warmer, and that an undertank heating pad should be used. Thing is, I have never used one before. I purchased one that covers one side of the tank-it is 8" square. Now, do I leave it on all the time, or do I shut it off at night like the overhead? I have a fairly thick layer of paper towel as substrate; the water dish is away from the undertank heater as is the food dish and calcium dish; the moist hide is out of the way as well. I have one hide in the hot side and one hide in the cool side. Should I be doing anything different? Thanks for any help.