the reason i don't really like undertank heat for basking is that most of my enclosures are naturalistic and thus, basking is done by laogen lights on timers and the UTH is, if used, only for the substrate heat to get the nitrogen cycle started and help keep the humidty and evaporation in time with plant resperation. In a ball python tank, i would rather create a model were by the basking area were spread out over a larger surface and make the light and heat emitters provide the right temps, and the lower end of the heat spectrum just warms that lower substrates, burrow and such. I hope this made sense, it's much better as i'm a kenetic teacher...