Bear with me here, this will take a bit of explaining.

I started out using a Hyrdrofarm thermostat. To get a hot spot of ~90F I had to set it to 80F which makes no sense since if anything it should need to be set higher to offset heat lost. I just chalked it up to being cheap.

Then I got a Herpstat 2, same issue, 80F gave me a 90F hotspot through the PVC of an AP T8. This threw me, this thermostat is supposed to be accurate to something like .01F why would it need to be 10F lower than it should, was it related to the Hydrofarm having the same problem?

Now, I cleaned the cage recently and the temps bottomed out completely, I now have the thermostat set to 100F and it is reading 85F in the cage, nothing changed I pulled everything out and put it back in, this was a few days ago.

Additional details: In both cases the thermostat probe was between the flexwatt and the bottom of the cage. My Accurite thermometer probe is inside the cage under the corrugated wrap. The temp gun I have and the Accurite agree with each other. Nothing has changed in or outside of the cage at all except me putting in new corrugated wrap.

Last note, the temp under the corrugated wrap reads 90F while the surface reads 85F, before it was even and there should be no way it is losing that much through that little cardboard.

Thoughts? I'm afraid its going to go back to the way it was while I'm at work and cook my snake.