I just set up my tub and its a 24qt sterilite thats long not tall(about 6in. high). I have my uth covering more than half the bottom and it's hooked up on a herpstat 2, which I had to set to 85 to get 90 on the tub surface-I think this is due to the placement of the probe, I had to stick it on the bottom of the uth instead of sticking it on the tub first, above the uth. My house stays in the high 60s most of the time and my cool side is reading 73.9 when my hot side is 90. What should I do?