UVB, thoughts and rambles

[Lorrenee]

I've searched the forum, and while I've found some answers I still find myself asking questions.

I currently do not have a bts (*sob*), but I do have a bearded dragon. The UVB recommended for them is always the Reptisun 10.0 tube (or Arcadia 12% which is in the UK I believe) or a MVB. Other bulbs have been known to cause eye issues and infections (ie: compact, reptiglo, etc).

1. Have there been any studies on blueys regarding eye issues from certain brands of UVB?

2. As far as percentage, we'll say, is more always better? Reptisun also comes in a 5.0, and I've seen reptiglo, I believe, get as low as 2.0.

3. Now, for a beardie, if using a UVB tube it must span at least 3/4 of the tank (give or take). When using a mvb, this doesn't apply, which is odd if you think about it hard enough. Do you think the same would apply for a skink? I've seen some tanks for blueys which only have the UVB on the basking side, others span the whole tank.

4. Mvb, what are your thoughts? Beardies bask all day every day, so being under the light wouldn't hinder their ability to absorb the uv. Skinks are explorers and diggers, correct? They wouldn't spend all their time basking like a beardie. Do you recommend mvb even though the uv would be focused on one spot?

I've seen the discussion thread about uv, and I know it's still a debated subject. I believe that I will personally include UVB in my setup, I just need to know the best way to provide it! There will be outside play time, but only when it's not a bajillion degrees during a Texas summer day!

[saisaac]

1. I have not seen any studies on blueys in particular and specific products, but I do know that there were a number of blue tongue skinks, bearded dragons, and others that suffered a number of eye issues when exposed to the initial wave of CFL UVB bulbs. It was theorized that small cracks in the phosphor lining of the bulb allowed dangerous UVC to escape. UVC can actually damage DNA, but the UVC emitted by the sun does not reach us due to the ozone layer. The affected animals had bulging eye or refused to open their eyes. I spoke to reps from Zoo Med at the HH Backer Pet Industry Expo this fall, and they deny that there was any conclusive evidence of this happening. However, I have seen some pretty detailed discussions, tests, and images that showed otherwise. Regular household CFLs can emit UVC at short distances as well, therefor, it is generally recommended that even in your house you use fixtures that have glass diffusers on them if the bulbs will be close to you.
This link discusses some of the issues with those bulbs:
http://www.uvguide.co.uk/phototherapyphosphor.htm

2. A 5.0 bulb puts out pretty little UVB as it is so I would assume you would want to go with a 10.0. Providing the ability to burrow and go into hide allows them to escape it.

3 -4 The reason you only provide UVB at one end of an enclosure when using a MVB or Metal Halide for UV is because those bulbs have a much higher output of UVB closer to that of open sunlight (but generally still lower) whereas a fluorescent bulb such as a Reptisun 10.0 or Reptiglo 8.0 are closer to the UV they might experience in the shade. If you did around on some other forums (there used to be loads of discussions on UVB lights on BeardedDragon.org) you can likely find posts where users have used UVB guages/testers to measure the exposure from various bulbs. As long as you provide a proper temperature gradient I see no reason why you couldn't use a MVB for a bluey, but the bulb would need to be at least 12" from the top of your bluey. In my opinion, since it does not appear that blueys need high levels of UVB (some argue none at all), I would think you would be better off using a fluorescent bulb that runs 3/4 the length of the cage including over the basking area and then use a halogen flood for heat. This way you can use a raised basking area which will require less energy to heat.

Here are some fairly good articles on UVB and reptiles:
http://www.uvguide.co.uk/whatreptilesneed.htm
http://www.reptileuv.com/why-use-megaray.php
http://www.reptileuv.com/uv-research-information.php