I'm not stupid, though my wife may disagree. I said put it on the back side because the size of the probe you described would make mounting between the uth and glass troublesome and i dont want it in the tank. Find the temp you want inside the tank with a thermometer, then set the thermostat. It doesn't matter if one side of the uth is hotter. You are setting it based on thermometer temps, not thermostat temps.
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