My blood freaked out when given a hot spot of 80 and where I live now, they keep the house at 65F and I wanted an ambient of 81. So I have some 3" flex watt around the sides of my tub, and a piece of 11" flexwatt on the top of my bloods tub hooked up to a thermostat. The thermostat has to be in 88-90's to get it to stay at 81 sometimes..

I'm still fiddling with the temps.