Lighting Options

[Odonata]

I am just finishing my enclosure (will update other thread with pictures shortly) and am in the process of working out the electrical components. In regard to lighting:

For an enclosure that is 4 foot deep would it make most sense to mount 2 T5 High Output fixtures in order to get a reasonable spread? The units that I am looking to install are:

48" HO T5 Double Bulb fixture with Two Arcadia 12% Bulbs

http://www.lightyourreptiles.com/48hot5dobufi3.html

The height of the enclosure from the surface of the substrate to the top is 40". Obviously I can hang the units so that they are a specified distance from the surface - I am considering placing them about 30" high, does this seem reasonable?

I have a number of Powersun MVBs and could use a couple of those for a basking spot, or would it be better to forgo that and just use some regular basking spots?

 

[Roadkill]

I've yet to try the Arcadia bulbs to give any real insight, but my experience with other bulbs would indicate that that kind of distance would invalidate any UVB output. With flourescents, about the maximum that any useable UVB will penetrate is usually about 2'. Other T5s I've tried definitely have an intense initial burn which would indicate that greater distance would be acceptable, but they quickly burned down to be comparable with other bulbs.

 

[Skeetzy]

I have an Arcadia bulb in my beardies cage. He does seem to be a bit more active than with the reptisun 10.0. LightYourReptiles.com does a fantastic job shipping the bulbs. Had 4 layers of cardboard taped around the bulb, in a box full of packing materials. Came with some freebies too.

 

[laurarfl]

I heard something recently that the Arcadia bulbs were really high output and needed to be used with caution.

 

[Deac77]

Reptisun is now producing a T5 bulb I think I'm going to try it

 

[Odonata]

Arcadia seems to claim that with 2 of the T5 HO units the distance can extend to 36 inches - I agree it seems like a long way. I guess I need to look into a meter to test the UV output to determine the appropraite range. I was planning to mount one of the fixtures close to the front of the enclosure and the other around 2/3 of the of the way to the back wall. I will mount them so they are height adjustable.

Even the new ZooMed Reptisun T5 seems to claim a significant range that is similar:

http://zoomed.com/Library/ProductDBFiles/UVB-Reach.pdf

 

[Roadkill]

While charts like those are useful, they have a problem in that they promote the hobbyist to think they are absolute. They are not. UVB doesn't have a "range that it will travel", like any other electromagnetic wavelength, it will travel until it is impeded. Clearly, opaque materials such as walls, screens, etc. will stop UVB. Glass, plexiglass, lexan, etc. will absorb a significant amount of UVB. So too does air. Specifically, the bonds between ions (particularly those between oxygen ions that are in a triatomic configuration - ozone) absorb this energy, usually breaking the bonds. So if you think about it, there are going to be environmental factors where you are using the bulb that significantly affect how far the UVB from the bulb will penetrate into your enclosure. First, the higher the intensity of the bulb, the more wavelengths that can get by before being intercepted - basically this translates into further distance. Atmospheric pressure/altitude will also significantly affect UVB transmission. Higher pressure/lower altitude means there will be higher density of air molecules to intercept, thereby reducing the distance of penetration. Higher humidity will also have the same effect, as will dust motes in the air. Then there's the ozone I specifically mentioned earlier. Most people seem to think ozone in the atmosphere is somehow restricted to the ozone layer; it isn't, this is just the layer that significantly absorbs UV radiation and therefore protects lifeforms below. By far, the most ozone is actually at the planet's surface, it takes a long, long time for it to rise to the ozone layer. The ozone at the planet's surface is produced in a number of ways - lightning, by-product of industrial processes, and most significantly for this discussion - electronics. Electrical systems typically have a few "loose joints" where electrons can escape and promote formation of ozone in the surrounding air, especially older equipment with higher functioning voltages and electrical "shortages". Electrical coils and transformers are amongst the worst. So, to bring the story to full circle, if you have a lot of electronics in your house, it is likely affecting the UVB output in your reptile enclosures. Bottom line, keep in mind those charts are guidelines only, and even they indicate that at the longer ranges the intensity is weaker, they just don't give any indication of how weak (I guarantee you it is very attenuated).

 

[Odonata]

Thanks for all the info Roadkill!

I thought I would update this with some information since I have had the lighting running for a little while. I am still trying to get everything just right in terms of appropriate temperatures and the desired timing of the separate systems. A few observations on the Arcadia lighting:

• Ordering, shipping, and how everything was packaged was excellent.
• The lights arrived each with 2 - 12% T5 HO bulbs as well as a spare daylight bulb.
• The units themselves are well constructed and the housing itself is metal, though there are plastic end caps.
• They are not specifically designed to be placed within an enclosure as you have to modify the housing to add appropriate hardware to hang them.
• That the units are metal and sturdy makes it fairly easy to drill and bolt on hangers.
• The units run very hot. This surprised me and is a problem as I did not account for the amount of ambient heat they would emit.

Due to the heat output I will be removing one of the units and stick with just the 4' dual fixture. I will re-purpose the other one for our beardies. For a very well sealed enclosure the Powersun 160's also emit way too much heat. I have swapped those out and gone with standard 50W floods to provide the basking heat, and lowered the Arcadia now relying on that solely for the UVB. I should have realized it was overkill had i done a little more homework on this prior to ordering the lights....live and learn!

 

[Roadkill]

Fluorescents indeed put out significant heat, everyone erroneously thinks they run cold. At my one place, I used to have a lot of people remarking on the heat in there and how my power consumption must be horrendous to heat that space. I never heated that place deliberately, the heating was entirely from all the fluorescent fixtures I was using.