Thanks for answering. The ambient temp is getting as low as 75f. That's way too cold. I'm really worried about him.

So, it's necessary to run both the UTH and CHE at the same time? I've heard some keepers just run CHE only? Do you think running just a CHE on a thermostat would be enough?

Also, I have my UTH thermostat probe sandwiched between the UTH and the glass, but where are you supposed to put a thermostat probe for a CHE?