[Sorry for posting a little late in the thread...was in the hospital for 2 days].
Regarding artificial UV lighting...someone mentioned certain bulbs were harmful to certain reptiles. I'll describe what I know below:
Compact Florrescent bulbs (both "spiral-shaped" and "U-shaped") or CFBs - These bulbs are commonly offered by Exo Terra, ZooMed and Zilla. They also come in 3 main intensity ranges: 2.0, 5.0 and 10.0.
There have been alleged (meaning I have yet to see the actual text myself - only heard about them secondhand) studies that show these bulbs have caused blindness in bearded dragons. I do not know which agency did the study, which brand bulb, which intensity (2.0, or 5.0?), or if they included other reptile species. So one could take what I just described with a grain of salt.
However, I can attest that other tortoise keepers as well as myself have personally witnessed temporary blindness on our tortoises, using both 5.0 and 10.0 bulbs of various brands, and regardless of how the bulb was mounted. [NOTE: studies have shown that CFBs are to be mounted horizontally in a specifically-designed fixture for maximum and most efficient UV emission and not to be mounted in a traditional dome fixture.
Standard Tube Florescent bulbs (tube bulbs) - also in various brands, and come in 2.0, 5.0 and 10.0. Oldies but goodies. Very few issues reported with these bulbs, the most common one being a short lifespan; about 6 months. The advantage is that they can over a wide area over the enclosure.
T-5 "thin" Tube Florescent Bulbs - same as the standard tubes, but thinner, and a little more efficient and a little more intense. I had personally witnessed my own tortoises going blind with 5.0 and 10.0 with one of these, so I would use caution. They reportedly have a longer lifespan than standard tubes as well.
Mercury Vapor Bulbs - The two-in-one heat and UV bulb! This is a two-edged sword, as you have to find the right spot to mount to achieve the right temperature for basking and still let the animal get adequate UV, because it still only produces a focused "beam" of heat and UV, and is not widespread all over the enclosure. These traditionally only come in high wattages, 125 and 160 watts, so use a temp gun when using one. I suggest only for small desert lizards like, ackies, beardies, Uros, plated lizards and juvenile monitors. I would not recommend for larger animals or tortoises.
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Here is the site where I got most of the above info from:
UV Guide UK - Ultraviolet Light for Reptiles - UVB reptile lighting on test
I can try and dig up a cool thread from a tortoise site that had some cool pics from thermal images on basking tortoises using different lighting situations, later.
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