Custom Enclosure: UVB Length Help

[gj1980uk]

So I am building a custom enclosure out of a solid wood dresser that I was gifted by my in-laws. Dimensions will be 52" Long x 20" deep x 22" high. Need to get an opinion on the length of UVB bulb needed.
I plan on getting a fixture for a T5 Repitisun 10.0, and am wondering whether I need a 36" fixture or if a 24" fixture will be fine. It will be mounted over the basking spot and I plan on building the basking spot so it sits roughly 12" below the UVB.

Will a two foot fixture be long enough or should I go with a three foot? I am thinking with the bulb over the basking spot, and with me building fake rock walls/hide etc, there would be enough UVB gradient with the two foot fixture, but wanted a second opinion....

Also, I am a little confused over fixture length vs bulb length. All the fixtures I have seen say 24" or 36", but the reptisuns on petmountain say the bulb length is 22" and 36". I presume that those bulbs will fit in their respective fixtures?

Thanks for your help. I am building this in my spare time (which is minimal with three kids!) and will post the finished project to the DIY forum when it is done.

 

[CooperDragon]

I agree that as long as you have it over the basking area, the 22/24'' will do well and create a nice gradient. You'll still get late morning sunlight levels of UVB over the basking area and the extra space on the cool end will provide a nice gradient down to low/no UVB. You may want to mount a secondary fixture in place over the cool side or center so you can install a ceramic heat emitter or heat projector for nighttime heat or supplemental heat if needed. Don't need to use it, but easier to install it while you're putting things together. The difference in numbers for the bulbs is that the fixtures stick out from the end a little bit so the bulbs are 22/34'' and the fixtures are 24/36''. I'd go with either of these:
This fixture http://www.amazon.com/Sunblaster-904296-NanoTech-Fixture-Reflector/dp/B00AKKUBDQ
With this bulb http://www.amazon.com/Zoo-Med-ReptiSun-10-0-Lamp/dp/B00AQU8HAO/

Or this combo set http://www.lightyourreptiles.com/22-t-5-ho-fixture-high-output-with-arcadia-d3-12-ho-bulb/


Keep in mind that the fixtures will take some vertical space in the tank so 12'' down from the bulb will be lower than 12'' from the ceiling. My Arcadia bulb and fixture are 2'' tall without any mounting equipment.

 

[gj1980uk]

Thanks for the advice. One question. Is the reflector on the fixture necessary or recommended. I could probably get a fixture at Walmart for a fraction of the price. But if a reflector is recommended, I'll go with the suggestion.

 

[CooperDragon]

I like the reflectors because they concentrate the output and allow the UVB to reach greater distances. The grow lights/HO fixtures for T5 bulbs are also a good idea because they can drive the bulbs to their full potential. The walmart fixtures don't really provide optimal output. For some comparisons, I'd take a look at the chart Taterbug put together. It shows the outputs from different bulbs with and without reflectors. https://sites.google.com/site/thelizardmadness/lighting-guides

 

[Taterbug]

Check the wattage and type of fixture again - Walmart doesn't sell T5 HO fixtures that I know of. Aluminum foil reflectors do an ok job but I've found most good T5 fixtures have them already built in.

The reflector redirects wasted light back into the enclosure and effectively doubles the output. It means you can mount it further away or have a stronger exposure. The link cooper shared illustrates when a reflector can help, be needed or be too strong.