So under tank heater, are you reffering to a heat pad basically? I just want to make sure I get this right. I do have a light we bought for the T's and don't use. I am not sure what type of bulb it can take and what wattage.

This is what I have
Exo Terra Compact Fluorescent Terrarium Canopy - Reptile - Free Ship - PetSmart

And we have this type of bulb but I don't think it produces any heat
Exo Terra Night Glo - Heating & Lighting - Reptile - PetSmart

Is there a bulb I can get that will work in that?