Ok. Well I just finnished my first new rack. It is a closed melamine rack and houses six 41QT tubs. I using 12" x 12" heat tape for belly heat. I using a loose substrate (cypress right now because I already have it from the cage). I am getting close to ideal temps. Should I measure the bottom of the tub or the substrate for 90-92? My tub bottom reads 96 and the top of a thin layer of cypress reads 92. This is my hottest tub which happens to be my third from the top. (I expected the top one to be the hottest but things seem to end up weird for me lol).
So where should I measure hot spot temps from?