Forgive me for asking but can you be a smidgen clearer. The cool side is reading 79 but in the cool hide, it's reading 103? The heat mat (uth) is set to max at 91 so what is reading at 86 degrees? And yes, a thermostat is highly recommended just to keep track of everything.

If the inside of the hot hide is reading 103, then it's likely the heat build up inside from the uth pumping out 91 degrees of heat. You'll definetely have to adjust that. I hope I got your readings correctly.

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