UVB ratings on bulbs mean.

[spaceclown]

First off I'm a new tort owner. Im going to start measuring the UVB from my florescent light in my torts inside enclosure. I'm currently using an Aqueon 00728 fixture with a 7% UVB bulb.

My questions are. What does the 7% mean. As UVB light in in the range of 315 - 280 nm range. How does a bulb produce 7%? What readings should I expect from my UVB light meter?

 

[ascott]

Too technical for me...lol...here all the grown torts are out all day and night and the smaller ones that reside inside get tossed out in the sun a few times a week if not every day for awhile...so I don't run uvb inside well except for the two RES tank..and they get tossed out in their outside dip once a week for a couple hours as well...but my post will bump your thread back for the others to see....good luck and if all else fails I bet you can do a good online search with your technical questions...good luck to ya..

 

[jaizei]

The number is the percentage of light that is emitted as UVB, compared to the total light emitted. So 7% of the light emitted (both visible and UV) is UVB.

 

[spaceclown]

Can you measure that percentage? It's confusing.

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I think I'm catching on. Basically UVB has its own wavelength which is a constant. But the amount of of UVB you receive is measured in uW/cm2 which is basically amount compared to distant. Hence the closer you are to the source the more UVB you'll get. So I only need to worry about what the correct amount of UVB (uW/cm2) would be at a certain distant to help vitamin D production and calcium absorption in my tort.

With all that being said. Is there a chart that tells me what the proper UVB would be at a certain distant for my tort.

On a side note it would be nice to be able to measure that 7% to ensure that I'm getting what I paid for.

 

[Madkins007]

More realistically, the numbers are marketing tools. They have little connection to reality, but allow you to compare bulbs from the same maker, thus a 10 offers the most UVB, a 7 offers less, and a 5 offers about 1/2 that of a 10.

A study of breeding chameleons found that they did best under low-level, low-wattage UVB bulbs left on for 10-14 hours a day. This makes sense to me- all-day low-level in captivity would probably equal the higher output of the sun when you factor in the level changes during the day and the effect of hides, etc.

 

[jaizei]

http://www.uvguide.co.uk/index.htm

This site might help some.