Question about Heat!

Ok so I just noticed that when I use a temp gun and check the heat tape it says 91*F but when I check inside the tub on the hot spot its 94-97*F.

I also noticed that on the same strip of heat tape in one spot its 94* and on the other side it was 104*!

Does this mean the heat tape is bad? Or the thermostat? Im currently using a Repstat Digital Thermostat set to 90* but most of the hot spots in my tubs are 95*?

Is this bad? The Room temperature is a constant 80*F. Any help is appreciated, thanks.

mine varies too, but the trick is to hold it closer. If you hold it farther away, it'll read a wider range of temps. My guess is that your heat tape is hotter than you have it set for, say the 104 ... whre is your probe? It should be directly on the heat tape. I have mine foil taped down with no issues.

my probe is also taped down to the middle of the heat tape. But I also have another rack where its not a digital thermostat. I just hooked the heat strips to two power cords and plugged those two power cords into the thrmostat. Its just a knob so I have been trying to adjust it using my temp gun but cant seem to get it set.