Instead of sticking the UTH to the tank, I stick it to aluminum foil. Go slowly so the foil doesn't get wrinkled. Then just use heat tape to stick the UTH to the bin or cage bottom. I also put the probe on the mat before putting on the foil; that way, the probe doesn't dislodge. Use a t-stat.
If your UTH is melting or discoloring your bin, it is too hot. People are 98.6 and we don't melt the bins. A car trunk in summer hits 100 easily and the bins don't melt.
