from here
http://thetegu.com/showthread.php?571-New-Mega-Ray-Mercury-Vapor-UVB-bulb
Quote ''
However, there is a word of caution I always try to get out when people are talking about the area of UV and which products are better. Whereas it is shown that UV is not only beneficial but in fact necessary for a lot of reptiles, there is NOTHING in tested literature to indicate that "stronger is better". In the current topic, longer lasting is indeed better, but reptiles are not immune to irradiation damage. Compare a wild, freshly caught lizard with any indoor-kept captive one, and not only is the general colour usually brighter, but their pigments are often darker. There is a reason for that - UV protection. Melanin and other pigments in the skin act as something of a "shield" to help absorb dangerous UV irradiance before it reaches deeper tissues and causes dimerization of DNA or other photo-induced damage. With UV, more or greater is probably NOT better. People often have the misnomer that desert reptiles and others have a need for stronger UV sources because of the environment they're in, but the truth of the matter is most desert reptiles spend a lot of time avoiding the sun. On the flip side, even we need UV to produce vit D3 and avoid SAD, but we all know where too much exposure can lead us.
My strategy on the matter is to approach the situation that reptiles are like batteries - a slow, mild trickle of charge (or UV in this case) will keep them topped up, but a strong or sudden jolt can cause a lot of damage. Trouble is, most bulbs on the market hardly even provide the "slow, mild trickle".
http://thetegu.com/showthread.php?571-New-Mega-Ray-Mercury-Vapor-UVB-bulb
Quote ''
However, there is a word of caution I always try to get out when people are talking about the area of UV and which products are better. Whereas it is shown that UV is not only beneficial but in fact necessary for a lot of reptiles, there is NOTHING in tested literature to indicate that "stronger is better". In the current topic, longer lasting is indeed better, but reptiles are not immune to irradiation damage. Compare a wild, freshly caught lizard with any indoor-kept captive one, and not only is the general colour usually brighter, but their pigments are often darker. There is a reason for that - UV protection. Melanin and other pigments in the skin act as something of a "shield" to help absorb dangerous UV irradiance before it reaches deeper tissues and causes dimerization of DNA or other photo-induced damage. With UV, more or greater is probably NOT better. People often have the misnomer that desert reptiles and others have a need for stronger UV sources because of the environment they're in, but the truth of the matter is most desert reptiles spend a lot of time avoiding the sun. On the flip side, even we need UV to produce vit D3 and avoid SAD, but we all know where too much exposure can lead us.
My strategy on the matter is to approach the situation that reptiles are like batteries - a slow, mild trickle of charge (or UV in this case) will keep them topped up, but a strong or sudden jolt can cause a lot of damage. Trouble is, most bulbs on the market hardly even provide the "slow, mild trickle".