I agree with not using incandescent lighting for aquariums, I think it drys the air out too much. I prefer flourescent lighting for light if any and an under the tank pad for heat. ANY heat source can burn your snake if it's not regulated. I've used both thermostats and rheostats (dimmer switches) successfully. Set the heater so that you have a hot spot in the low 90's (between 90-93 is about right). My opinion is that people make too big of a deal about ambient temps in the rest of the tank and I think whatever your room temperature is should be fine.