Quote Originally Posted by The Serpent Merchant View Post
First off your thermometers aren't reading the correct temperatures. UTH's don't increase the temperature of the air in the tub so your non-probed thermometers are 100% useless. You need a probe to measure surface temperatures.

Second a UTH will NEVER change the temperatures of the cool side, once again because they don't change air temps.

Your substrate is too thick as well. For a UTH to work properly the substrate needs to be no thicker than 1/2"
Awesome! Thanks for your response. There's definitely a learning curve here for me with these UTHs, so they're taking some adjustment. I was under the impression that the UTH heat transferred through the material it was adhered to (plastic, in this instance), and the heat dissipated into the air, warming it...which is why I used a non-probed thermometer. Now the term "belly heat" makes sense. D'OH. Glad I have a UTH for each side then! So I'll decrease the substrate thickness and get a probed thermometer...or two. Any suggestions for cheap probed thermometer buys? I couldn't find a probed Acurite at the Walmart I went to...