Thermostat setting on rack

[Annarose15]

I'm running my rack before I put my snakes in, using eco earth as a substrate, and my thermostat is set to 100 but the temp inside is only 75... What settings do you use for your set up, and/or should I switch to a less dense substrate?

When you say "the temp inside" do you mean ambient temps? Belly heat (flewwatt, heat cable, etc.) is not intended to raise ambient temps, only the hot spot. Are you measuring the surface temp of the tub directly over the heat source? What are you measuring it with?