This is my first time running heat tape with tubs and a herpstat, I also have a laser temp gun I've been using to moniter the temps. I don't have any snakes in the tubs yet, I'm picking up a few more at the expo next weekend, I'm just trying to get my temps and everything dialled in before they arrive.

I have normally had snakes in terrariums with heat mats hooked to rheostats, so this is my first time setting up heat tape and the herpstat. I'm just struggling to achieve my 90 hot spot. I have the heat tape taped down, the tubs have little legs so they are raised slightly off the heat tape. I have the probe in the centre of the heat tape, I started with the temp settings set to 110 to try and achieve the 90 at the top of the substrate, which is aspen, but I was barley pushing 82-83, so I've been slowly increasing the temp settings, I'm up to 120 and at like 85, do you guys think it's cool to just slowly raise the setting until I reach 90 at the top of the sustrate? Or should I be worried at how hot I'm setting the heat tape? Is it normal to have such a temp descrepancy between the settings and the temp achived at the top of the substrate? Thanks