Hmm. I guess I'm doing something wrong. Lol I have my t-stat set to 80 for an 84 degree hot spot. It's about 86 between the tub and heat tape, and 83-85 above the pine.

I have my heat tape snaked through the rack, and my t-stat probe is on a part of the heat tape that isn't under a tub. <--I think that is why, but it's working great.