I have a an 18x18x18 exo terra setup with an 8x8 UTH under the hide. I simply placed spacers on the bottom of the UTH to let it set off of the stand instead of adhereing it directly to the tank. I plugged the UTH in through a Zoo Med Repti-Temp Rheostat in order to adjust the temp and placed a thermometer probe using the suction cup right above the UTH. The problem is even with the Rheostat adjusted to its lowest possible setting the tempature continues to rise into the 102 degree range. Could the rheostat not be working properly or should a move the probe inside the tank underneath the hide. The ambient temp is staying between 80 and 85 degrees. I really don't want the belly of my ball burned. So I was thinking of just unplugging the UTH until I get back to the store tommorrow. As long as the ambient temp stays around 80 he will be fine right?