Basically reptiles need at least 13 to properly synthesize d3. Natural sunlight tends to be between 50-300 in most places.
The measurement is ; 1 µW/cm² (microwatts per square centimeter).
From my own readings. 5.0 tubes through screen don't give enough UVB unless that particular chameleon is directly under the bulb, maybe 1-2" from it. So I stick with 10.0's and Arcadia's.
Thanks, at the top under the light on highest branches I'm getting low 20s. I'm using 5.0s through screen, all five 48" are new and putting out Same numbers.
With those numbers you are fine for now. I play everything on the safe side. I use only 10.0 and when the get down to 25 I set them aside for new born's.
I am waiting patiently for my other Arcadia's to arrive, I will be using those even with them being more expensive. I have used my first two sets for over 2 years and they still read in the 30's and that is with them about 10" away and through screen cages. Worth the extra money to me. They will more than pay for there selves in the long run.
Thanks everyone for your input. I'll be getting Arcadia bulbs after I go through these bulbs and the next set of bulbs I have for 6 months from now. Lol.