From
http://my.pclink.com/~dkelley/igcare.htm#wat
"It has long been thought that full-spectrum bulbs are necessary for iguanas to produce Vitamin D3 which helps iguanas absorb calcium. Recently, studies have been done that prove that this type of lighting DOES NOT work to duplicate natural sunlight. In fact, in a study done by Dr. Fredric L. Frye, it was determined that you would need 6 to 8 of these lights(commonly called Vitalites) within a few inches of the iguana, 12 to 14 hours a day to have any effect at all. We also know of a university student who did her master's thesis on full-spectrum lighting for reptiles. She used living tissue samples for the study and came to the same conclusion as Dr. Frye. Studies have also been done to show that iguanas can absorb Vitamin D3 through a proper diet. Full spectrum lighting can give off light that LOOKS similar to natural sunlight, so it may be psychologically beneficial for your iguana, but if you are just buying the light for calcium absorption reasons, don't waste your money. Instead, if you can provide them as much natural sunlight as possible, along with a good diet, this would be a far better thing to do as well as cheaper. There is no replacement for the benefits that your iguana can receive from natural sunlight. It does wonders for their coloration and their overall "pep". Remember to always provide your iguana with some shade to get out of the sun if they wish, and to never bring them outdoors in a glass aquarium as the heat inside the tank will quickly rise to lethal levels."
Knowing Frye is pretty well known for his research and stuff, i figured i'd share...i never heard it quite like this before...only that some lights are better than others....anyways, im not jumping to conclusions...im still using my lights.
