What I do is slide the UTH under the tank without adhering it to the tank. So basically the waxpaper or sticky side is on whatever the tank is sitting on(piece of wood, dresser, etc.). There is usually a little gap there between the surface of the tank and the bottom once this is done and I just put the probe there rather then in the tank. The snake will most deffinitely move it, and tape is a bad idea as well so don't do that. It works for me perfectly. Put the probe on the surface of the tank to make sure the thermostat is where it should. The gap might make a little difference.