My tub is getting tough to set the temperature to any fine degree. It's been that way for a while, but I was able to set it for 100 degrees and we're happy with that. But lately it was dropping, and got down to 95. It still functions correctly, in that the heater/pump turn on at 94 and off at 96. But when I just touch the control up a hair, it shot up to 105 and goes +/- 1 deg from there. Touch it again and it's down to 95 again.
Is this the topside panel, which is digital, or something in the main box in the base?