>>How do the bulbs lose their uvb output after 6 months.

>Cause it's light, not like a powder burning off of it for 6 months



I do not remember the exact mechanism, but it is absolutely true. It may actually have something to do with burning off powder or another substance.



> The light still hits all the wavelenghts and puts out the same intensity as it did when it is brand new.



How do you know this? I assume this is purely your own anecdotal observation. Remember, there are thousands of people out there with UVB meters that can quantify the UVB output of their bulbs.



>I just do what they say and replace mine every 6 months,



I personally feel that six months is on the more frequent side, especially if you're supplementing your pet's UVB exposure with frequent natural sunlight. Of course if you had a UVB meter you could accurately track the output decay and replace the bulbs only as needed. If you went with the Mega Ray externally ballasted Mercury vapor bulb I recommend in my post below, you could go for a year or more with the same bulb and still put out more UVB than a brand-new florescent!



Here is an article on UVB lights, and it may explain the mechanism for output decay...

http://www.austinsturtlepage.com/Articles/guidetolighting.htm
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"I know the human being and fish can coexist peacefully."

Governor George W. Bush, Jr.



"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."

Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)

[ Hide Replies ]

• every 6 months - KingGeorge69, Sat Aug 20 12:20:52 2005
• Lifespan of UVB bulbs - Colchicine, Sat Aug 20 12:41:40 2005