My Ig's name is "SATO the Destroyer"! Hes about 8 years old. I actually worked with a reptile vet and he had a uv light meter that measures UVA and UVB intensity: heres what we found testing different lights commercially available, flourescents will only be effective to the UV listed @ 4-6" distance with no interference, anything farther than that is a waiste of energy. The best bulb we tested was the T-Rex UVB which is essential a mercury vapor, this baby was only a 100 points lower than the 12:00 pm direct sun. Granted thats a lot of UV so you have to use it wisely. I grew my Black Throat under this and my mature Ig and was very happy. They are expensive but can be found online for half retail. I should state that there is no substitution for unfiltered sunlight as nature is complete and we are, well human!