Just letting you know, while the picture doesn't show it very well. I have air holes on all the sides and the top of the tub. But I'm seeming to have one problem. With the rheostat plugged into the UTH I cant seem to get a consistent temp. It will stay steady for some time then when I come back to check on it, the temp has gone up about 10 degrees. Is there a way with the rheostat to make it stay consistent or should I plug a thermostat into it as well?