how low does your cool side run? I don't use a uth at all, just the heat lamp. u shouldn't need to use a uth on your cool side unless your house is crazy cold. insulate your tank will help. also, buy a temp gun. I got one locally for $20 at a hardware store.
also, are you using a basking light bulb or an infrared heat bulb? the red colored heat bulbs are best. run it all the time and not worry about turning it off.