Do screen tops filter UVB rays?

[EmJagsz]

Does anyone know? I have the ReptiSun 10.0 tube florescent bulb, and it says it reaches up to 20 inches and all, but will a screen top filter the rays? The box says it won't, but sometimes I'm not very trusting of boxes..
I just need to know if they filter or not. I recently lost a beardie because I thought screen filtered UVB rays and I went and cut part of the screen from under the UVB to prevent it from being filtered. It's just unfortunate that I ended up making it possible for my cat to squeeze his way inside the tank and ended up killing him..

So for future reference and for the safety of my future beardie...

 

[wes]

Well, it's a partial filter. The actual screen will block the UVB rays but the holes will allow it through. I wouldn't cut a hole in my screen top to maximize the rays, though.

The problem with kittens is that they grow up to be cats.

 

[EmJagsz]

It was a fine mesh screen, that's where I thought I had to "fix" things. The holes in the screen are about 1-2 millimeters wide, so you might see where I was coming from..... I plan on buying a new screen before I get another beardie anyway so that it'll be completely safe from any overly curious cats.. Thanks

 

[Twobeardieguy]

It filters some but you should be fine!

 

[wes]

It was a fine mesh screen, that's where I thought I had to "fix" things. The holes in the screen are about 1-2 millimeters wide, so you might see where I was coming from..... I plan on buying a new screen before I get another beardie anyway so that it'll be completely safe from any overly curious cats.. Thanks

You can replace it with another mesh screen. The holes in the mesh are small, but the metal is a much smaller percentage of the area. The wavelength of UVB light in the 320 nm - 290 nm range, which is roughly 0.0003 mm, so the waves can easily pass through 1-2 mm holes.

 

[EmJagsz]

Thanks guys

 

[Narwhal72]

A screen top can filter as much as 40% of the light produced by a fluorescent tube. And the finer mesh the more it will filter out. A large mesh will filter only about 25% of the light. The reason is because finer mesh has more solid material per square inch than large mesh.
It is probably not necessary to cut the mesh to let more light in. With a good quality lamp you will get enough UVB through the course of the day to satisfy the beardies needs even with a loss of 40%. To compensate you can use a fixture with a polished aluminum reflector. This increases the directed UVB output of the lamp by as much as 40% which puts you back to even.

Andy Hudson
Central Aquatics
Research and Development