i have my probe taped to the UTH on the back of the tank. That is, it's placed between the UTH outside the cage and the plexiglass. I have to set my helix at 98 to get 94 surface temp inside the cage. some people recommend keeping your probe on the inside for this purpose, but i worry too much about my snakes moving it. i'd rather just settle for being off by a few degrees to get the correct inside temp. While it's true that as my ambient air temps vary so will my temps inside the cage, I sleep better knowing that my snakes vary by a couple of degrees rather than having that probe bumped and cooking them.

Remember, these are wild animals which have existed for thousands of years throughout wild temperature swings.

JonV