The heat radiates into the shelving, which creates gentle belly heat and also increases the ambient air temps.
The problems with belly heat I have experienced are as follows:
1) If your thermostat breaks or your dimmer gets "bumped" into, a heat source that is directly underneath the tub can become very dangerous. Even if my back heated cable is going full blast the animal will not be directly exposed to the extremely high temps and will have a good chance of surviving by moving to the cool side of the tub.
2) When heating a breeding rack from the bottom sometimes the females will push the lay boxes directly over the heat source. Lets say your heat is set to 89-92*f (surface temps). The damp lay medium can allow the heat to build up and can get hot enough to kill freshly laid eggs. When heating from the back it is impossible for the lay box to come into such direct contact with the heat source, an added degree of safety in my opinion.
3) Back heat creates a better thermal gradient. I can achieve a perfect thermal gradient when heating from the back.
I still heat from the bottom for my baby geckos. But all the other reptiles in my collection are getting back heat or will be getting switched over in the coming months.
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-Ross Payan - www.LeosAnonymous.com
Leos Anonymous
Ball Pythons, Red Striped Leos, W.Hognose and Screaming AFT's
