I have a 15 quart plastic tub, with a 10 to 20 gallon repti therm uth. It's plugged into a heat mat thermostat. I have the uth heater foil taped to the bottom of one side with the probe between the heater and the bottom. It's currently set for the max temperature of 100 degrees, I have a probe thermometer on the inside of the tub hot spot. The highest temp I've gotten is 82 degrees. My humidity is good, I just can't get the temp to 90 inside the hide