Some quick tank questions

[Slim]

You want to put the probe near the top of the substrate, so it captures the heat of the ground the snake will be touching.

It's 1:00 in the morning, and your BP just moved the probe while burrowing down to the find that warm spot. The probe is now floating around in the air somewhere and the UTH starts really heating up because it's trying to hit your Thermo set point. Meanwhile your BP has burrowed down to the glass, and had no idea that it's burning its skin off the bone...

You want the probe secured at the point that will get the hottest and could be reached by your snake.