You have a thermostat between the UTH and tank, right?
You are losing a lot of heat to your room with the heat bulb that far off the tank. Your best bet is to get a light dimmer, set the bulb on top of the screen (use foil on top of that side for safety, with a hole cut out), and turn the heat down accordingly.
You should have a hot side of 90, and your warm side should be what your ambient temp is.
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