Okay, now I'm getting really frustrated! No matter how low I turn the dimmer, if I put the heater UNDER the tub, it reads well over 100 degrees. I must be doing something wrong with the probe, because I've never had that problem with UTHs before. So in desperation I put the UTH on top of the tub, and cranked up the dimmer all the way... now I'm getting readings of around 74/80 respectively, which is too low. ARGH!!! I'm about to give up and go back to the glass tanks, unless somebody can help me out. Any thoughts??

Edit: I'll try to get a picture of the probe up-close, but I don't want to bother Mona right now - she just ate a big meal.