What are you using to regulate the temps of the UTH? If you have a thermostat (or worst case, a rheostat) you can safely put the Sterilite container right on the heat pad. Attach the thermostat probe right to the UTH and the thermometer probe right to the floor of the tub. Then make your adjustments based on the actual floor temperature. That is where you want you 90-94 hot spot. Hope this helps and doesn't confuse further!

Jamie