UV lighting (Arcadia 12% questions about distance)

I have one bearded dragon and he’s my first one, I got him in April. I’m completely new to reptiles and I’ve been trying to do everything the best way so I just want to clarify something. When I got him, I was using a reptisun 10.0 mounted inside the cage. His enclosure is 48” long and the reptisun didn’t cover the correct amount so a while back I upgraded to the Arcadia 12% with a T5 HO fixture with a reflector. I have it on top of the cage because I was under the impression that if I mount it inside it will be too strong, but after more research I am confused by this

His enclosure is 18” high and there are some logs that allow him to be about 10” high - however I don’t mind removing these ones if I end up mounting the light inside.

His basking spot is about 6” high so he is usually 12” from the Arcadia 12% thru mesh screen. Is this too far? I know the mesh filters a lot so I want to make sure

Would it be fine for me to mount it inside his enclosure - or is that way too strong due to the reflector etc. (again- if I end up mounting it inside I’ll remove the huge wood thing that allows him so high up - he never uses that one and has a new custom one coming soon anyway so i don’t mind) and just in case it matters his Arcadia is 36” long, with the enclosure being 48”. I was originally going to get the one that would span across the entire enclosure but I learned that they should have a shady section with a gradient so I didn’t

Thank you for any help! ?

Hi there,

Depending on the mesh, it will filter around 30% of the uv.
Do you have a reflector in your fixture?

Here is arcadias recommendation for their own bulbs in regards to our pets, bearded dragons.
https://www.arcadiareptile.com/lighting/full-sun-baskers/

The t5 with a reflector should be no closer than 12 inches from the basking spot. So if you mounting it under the mesh causes your dragon to get closer than 12 inches, you're too close according to what Arcadia recommends, and according to what other leading reptile light experts recommend.

If mounting on the screen, you can calculate (or guesstimate) the amount of area the mesh blocks, and use that number to determine how close the basking surface should be if on the mesh.

An example - to make math simple let's just say your screen blocked 50% that means its half as effective so needs to be 6 inches instead of 12. If it blocks around 30%, it should be 8.5 inches.

So now you can determine for yourself if you want to mount it inside and make adjustments, or have it on the mesh and make adjustments.

Both ways are perfectly acceptable as long as you are maintaining proper distances.

-Brandon