can't go by what others are. you need to get a way of measuring your temps and also check each level of your rack. a temp gun is a very important piece of equipment. and ones like the pe-1 sold by pro exotics will do just fine and the price is on the lower end of temp guns. I tested my pe-1 with my high end fluke temp gun and it tested the same. since it's back heat. you don't have a hot spot in which the snake can lay on like belly heat. so I also check with a thermometer and when the snake is laying in the back of the tub. closest to the flexwatt, I will check her body temp with the temp gun. hope this helps you more than me saying what my herpstat for my backheated tubs is set at.