Not sure if it has been brought up yet, but do not measure your temps ON TOP of the substrate!
Measure your temps under the substrate, directly over the heat source. So INSIDE the tank, but right on top of the glass. If you measure the top of the substrate, then underneath of it can get a LOT hotter.
Ball Pythons will burrow or push the substrate to the side, and they can get burns if the heat is to high under the substrate.
A inch or so of substrate is enough and if the BP wants to get warmer, it will move some of the substrate...
