UVB Exposure... not as simple as they make it seem?

[BossLady3]

First this is by no means a bash on anyone but I get irritated when trying to do some research and Im seeing alot of the same information regurgitated by people who dont even understand the lighting themselves.

I know this because I have questions about it myself, and cannot find it after searching several days on MANY bearded dragon forums.

I am currently using a 36" T5 HO Arcadia 12% WITH reflector (lightyourreptiles.com) for my dragons and I dont know how far away to set the bulb. So I go the normal route and start researching... and all Im finding is 8 - 12" away for 12 hours a day. sometimes they mention a reflector and mesh, often times they dont. Im in the process of buying a solarmeter right now but even if I did have the meter Im at a loss because

1) how much UVB does a dragon need a day?
2) how many hours should I have intense UVB on the dragon?

if I were to set it a little closer to the dragon, could I shorten the time span per day? what are optimal readings to be seeing of UVB for the dragon? obviously you would want the UVA on atleast 12 hours a day, but with such a strong bulb as an arcadia WITH reflector, should I maybe only have that on for 5 - 6 hours a day??

so much confusion... as of right now theyre 12" away from the HO arcadia, but Im wondering if that is too close and I should get it further away OR simply not have it on as long. I want to create a habitat that can let them mimick as closely to their natural habitat as possible, but Im finding such conflicting information as to what they actually do in the wild.

some people say they DONT bask at the hottest/brightest/intense part of the day (noon) and do it shortly before and after those times, while other people say they do bask during those times yet these are the same people exposing them to low levels of UVB at 12 hours a day.

help!!

 

[diamc]

I have the Arcadia HO bulbs too. Because I have a basking area that is 6 to 12" from the bulb when placed on the screen, I discussed it with Todd from http://www.lightyourreptiles.com and he recommended the HO 6% bulbs so that's what I went with. Here's the link where I got the info about this particular bulb you're wondering about: http://lightyourreptiles.com/34t5hofihouw3.html

When I just looked at his site, this is the recommendation for the HO 12% bulbs and I will quote what he wrote

34" T-5 HO Fixture *High Output* with ARCADIA D3+ 12% HO Bulb * Comes Complete with Arcadia D3+ 12% T5 HO Bulb.

This is the perfect economical, light weight T-5 High output light fixture coupled with one of the NEW Arcadia T5 Bulbs.

High Desert UV output. Fantastic Light and UV A&B. Highest UV output of any Reptile Bulb. Minimum distance 14" - 24" Depending on set-up. Testing with Solarmeter 6.2 is highly recommended.

So, I would definitely go with what he stated. At that distance, there really is no reason why you can't have that UVB bulb on as well as the basking light for 12 hrs. I would NOT set it any closer because these high output bulbs put out a lot of UV index and it could affect his eyes and actually even burn his skin if too close. You also don't need a reflector with these HO bulbs. It's also important to have an area where your beardie can escape the UVB if he so desires.

I have the SolarMeter 6.5 and that way I can keep a close eye on the UV index and so far, it is staying between 5.0 and 6.5 so I'm getting good readings and the bulbs are only a couple of months old. When the UVI starts declining, I will probably be mounting it in the tank as also discussed with Todd so I should be able to get about a yr out of.

Hope this helps. Todd is great to talk to and will answer any questions or concerns you have. I spent about 1 1/2 hrs on the phone with him one night, he's very easy to talk to.

 

[scm133]

I have also researched, and asked questions. Very confusing. However, I did get encouraging words from an expert on my viv, and some idea of a good Solarmeter reading.I also have an earlier post from Frances Baine stating that 120uWcms or 3.0-5.0 UVI is good at the basking spot, just as long as you are able to give them a shade gradient. Hope this helps.

Reptiles/Answered Question

Expert: Tracie Kretzschmar
Subject: Arcadia T5 D3 12% with reflector with PowerSun Mercury Vapor 100W
Question: Hi Tracie,
I have a Bearded Dragon in a 4x2x2 viv. The Arcadia lamp is mounted on the top in the middle. I have the lamp closest to the hot side, and have good readings for shade on the cool side (30 uWcm2). The Arcadia lamp is 15 inch from the basking spot. The mercury vapor bulb is 12" from the basking spot. The combination of the two give me readings of 120 uWcm2, which I understand is equal to 3.0 UVI. My temps on the basking spot is 102-104. The temps on the cool side are 80-82 degrees. Is this setup ok? I have a 36x 5 inch screened cutout on top with three 3" circular vents in the back.

Answer: Hello Sally,
That is a great sized tank, that is the size we use also.  
Those readings are fine & the temperatures are great.  I wish more people would spend that much time for planning on the UVB placement & lighting.  
The UVI is variable, depending on the light you are dealing with.  That reading of 120uW/cm2 is great so it should yield between 3-5 UVI.
The Arcadia D3 12% tube bulb has a very safe spectrum.  The Powersun has been known to cause some eye issues due to some low wavelength but with it combined with the Arcadia D3 12% should be fine.  
Great job on the setup!
If you can, post a picture of your setup.  

Tracie