I have two pieces of Flexwatt heating my BP tank. One for the cooler side, one for the basking side. I've noticed quite a variation in the surface temp of the Flexwatt as you run a temp gun along the surface, or the bottom of the tank for that matter. It seems to run hottest in the middle width-wise, and gets cooler as you move towards the edge. Just an observation. I keep my stat prob on the middle so its reading the hottest spot.