First BP and need some help

[200xth]

Ya I always make sure to pop the top so I'm not reading another surface. If my substrate is too thick, then how much should I actually have in there? I'll also be switching soon to something that holds moisture a little better.

You can put what you want for substrate (within reason), but keep in mind your snake is going to burrow.

You want the hot spot to be hottest right where the UTH is under the enclosure. The floor right above that should be 90F (or whatever you want for your hotspot).

Get the hotspot on the floor dialed in to 90F (or whatever you want), then put your substrate on at whatever depth you want (within reason). Your snake will burrow if it needs to be warmer. But no matter what he does, the hottest he can get is still safe for him (90F, for example).