All UVB producing bulbs available for the reptile market produce UVA. They also produce various amounts of UVB. Most of the better brands of UVB florescent tubes produce indicated rating of UVB light (ie ones rated 5.0 produce 5.0 units (that funky u symbol with the longer foot...I am too lazy to figure out a way to produce the symbol here). Mercury vapor bulbs designed to produce UVB do produce much higher levels of it and are capable of pushing the amount further from the bulb than the UVB florescent tubes (florescent tubes effective range is between 6-12", after that, the amount of UVB declines). With MVB, they push it out 18-24" (probably more than that, but I can't remember exactly their maximum effective range). However MVB's can't be less than 18" above the basking sight as they can cause eye irritation in bearded dragons. They also have to be mounted in a completely vertical position (ie mounted straight up and down not at an angle) else they tend to burn out fast.



UVB producing florescent lights loose their effectiveness over time as well, hence the need to replace them every 6-9 months. After this time, their uvb outage is 50% or less. MVB also loose their effectiveness over time as well, but typically 9-12 months is when you need to replace them.



There have been testing done on many common reptile bulbs by people before, who have posted it there or have their results on their webpages. You can buy UVB meters to measure the amount of UVB put out by various lights, including the sun.



None of the common products for reptiles put out anything near what unfiltered natural sunlight does. The sun at high noon produces something like 200 or 250 units of UVB. Hence exposing your dragon to natural sunlight when possible is a great thing to provide. However not all of us have the ability to give an hour of sunlight 3-5 times a week for our dragons, either due to weather, amount of dragons, time etc. so all we can do to ensure the health of our dragons is to provide them artificially produced UVB lights, either florescent tubes or mercury vapor bulbs. Supplemental vitamin D3 is necessary for all indoor kept bearded dragons though care must be taken not to give them too much. It is a fine balance to ensure they have enough uvb exposure for them to naturally produce all the D3 they need to properly metabolize calcium and when we can't be sure they are getting enough UVB exposure, to add a little extra vitamin d3 via the use of supplements.



One website I know where some personal experimentation on how much UVB is put out by several different kinds of UVB producing bulbs is listed at the site below:



www.beautifuldragons.com
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PHLdyPayne

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