You can also put the thermostat probe on the bottom/outside of the UTH--just put a strip of aluminum foil tape on the cord of the probe (but not on the probe itself) to secure it to the UTH. It might not be quite as accurate as sandwiching the probe between the glass and the UTH, but it works if you made the mistake of gluing the UTH down before placing the thermostat probe (like I didand you have a thermometer probe to gauge the right temperature IN the tank anyway). Idk, it's probably easier than tearing your whole tank apart and scraping the UTH off.