Home | Product Reviews | Zoo Med Reptisun 10.0 High Output UVB Lamp and 5.0 UVB Lamp Product Review – Part II

Zoo Med Reptisun 10.0 High Output UVB Lamp and 5.0 UVB Lamp Product Review – Part II

Repti Sun 10.0 UVB Fluorescent BulbsLast time I reported on the Staten Islands Zoo’s use of the Zoo Med 10.0 High Output UVB Lamp (Please see Part I of this article). Today I’d like to provide some specifics concerning tests carried out there.

Test Results
The UVB output readings recorded at the Staten Island Zoo are as follows (note: measurements are expressed in microwatts per centimeter squared, the standard for measuring UVB output):

Zoo Med Reptisun 10.0 High Output UVB Lamp

Distance Without Screen Through Screen
6 inches 75 56
12 inches 23 18
18 inches 10 8

Zoo Med Reptisun 5.0 UVB Lamp

Distance Without Screen Through Screen
6 inches 32 24
12 inches 9 7
18 inches 4 3

As you can see, the basking site’s distance from the lamp has a major impact upon UVB exposure, as does the screen cover’s deflection of light rays. With a bit of creativity, basking spots within 6 inches of the lamp can be arranged in most situations, and this is certainly the way to go for many species. Where safe to do so, dispensing with the screen cover is another option.

Using a Separate Basking Enclosure
If a 6-inch basking site or uncovered top are not feasible in your pet’s terrarium, consider the possibility of utilizing a separate basking enclosure for a few hours each day. When keeping young radiated and star tortoises in high-topped zoo exhibits, where adequate UVB exposure was not possible, I rotated the animals into a low, uncovered container every day or so, and achieved excellent results.

If you go this route, be sure to keep your pet’s individual needs and temperament in mind. For example, a simple, open container that might suit a Greek tortoise would likely cause a good deal stress to a flat-rock lizard. High strung or secretive animals must be made to feel secure in the basking enclosure, or you may do more harm than good.

Reflectors and UVB Output
The group UV Guide UK has found that simply mounting the lamp within a metal reflector nearly doubles the UVB light that is available to basking animals. In addition to focusing all of the lamp’s light into the terrarium, I imagine that the reflector also helps by deflecting back some of the light that has bounced off screen tops or other structures.


An informative article on the role of UVB and basking behavior in Vitamin D synthesis is posted at:


  1. avatar
    Josh - TortoiseForum.org

    This is such important information that most people don’t get to read about. The UVB bulb can quickly lose its purpose if it isn’t properly fitted to the enclosure and given a close and direct path to the animal.
    UVGuide.co.uk is a great site for such research. I reference it a lot.

  2. avatar

    Hello Josh,

    Frank Indiviglio here. Thanks very much for your interest in our blob and comment.

    I agree…lack of information and misinformation is still common, although the situation is improving at least as regards the basics. I think the fine points are now important bring to light – proper positioning, as you mention, for example.

    Please pass along anything of interest that comes your way, and I’ll do the same.

    Best regards, Frank Indiviglio

  3. avatar

    If you ever get the chance could you measure these lamps through a peice of glass. There are many of us with high humiditiy environments that run glass lids. I am insterested in seeing if any UV makes it through a glass lid.

    • avatar

      Hello Jessie, Frank Indiviglio here.

      Thanks for your interest in our blog.

      There has been a lot of work done along those lines. Unfortunately, no UVB of any use makes it through glass, no matter how strong the lamp….in fact, even under direct sunlight, glass filters out all UVB.

      UVB permeable glass and plastic is available. I looked into it a few years back when I was helping design a new Reptile House for the Staten Island Zoo. It was very expensive and only available in large panes, but there may be other companies offering smaller units by now.

      Good luck and please keep me posted.

      Best regards, Frank Indiviglio.

  4. avatar

    Hi Frank, what type of screen were you using, was it the fine screen that comes with Zoo Med glass terrarium tops, and would there be a major difference in UVB transmission between the type of screen?

    • avatar

      Hello Chris, Frank Indiviglio here.

      Thanks for your interest in our blog.

      Good question. The tests were run on standard screen covers, which have a wider mesh than the Zoo Med tops you mention. Smaller mesh does indeed block UVB transmission to a greater extent than larger. However, subsequent tests revealed that, if the bulb is housed in a metal reflector (the typical situation), transmission is greatly improved even with very tight mesh – the rays bounce back and forth between the cover and reflector until they find their way through the holes in the mesh.

      Good luck and please keep me posted.

      Best regards, Frank Indiviglio.

  5. avatar

    Frank does the Repti-sun UVB light either 5.0 or 10.0 lose its strength if it sits unused for 3-4 months. I like to keep an extra one on hand so I have it when I need it – it that not a good idea. Thanks

    • avatar

      Hello Pamela, Frank Indiviglio here.

      Thanks for your interest in our blog. Good idea to keep extras on hand, I do the same. The UVB output only starts to decline once the bulb has been in use.

      Good luck, enjoy and please let me know if you need further information.

      Best regards, Frank Indiviglio.

  6. avatar

    Hello Frank,
    I am so pleased to see this article,,,especially after one recently regarding the coil/compact uvb’s. I am happy that you have made these studies available, and if you don’t mind I would like to add this article to our website.

    • avatar

      Hello Kelly,

      Thanks for your interest…I believe you mentioned the compact UVb’s elsewhere, perhaps on FB?…I recall an article on point, am looking into it.

      I’m pleased that you’d like to use the article. Please reprint the 1st paragraph, with a link to the original, i.e “You can read the rest of the article here…” This is in keeping with theguidelines of the blog sponsors. Thanks, best, Frank

  7. avatar

    Hello Frank, I just noticed that this is about the Reptisun 10.0 High Output, so is thiw r3ferring to the new bulb that just came out recently,,the T5 High Output or the regular Reptisun T8 10.0? Need to clear this up. Thanks,

  8. avatar

    Hi Frank: I would like to know if you have tested the new reptisun t5 high output bulbs yet. I am presently using the reptisun original 10.0 t8. I get a reading of 25 on the ground of my terrarium for my bearded dragon, I have it mounted inside the tank. I did try the megaray but Crete seemed to avoid it. I have a fourty gallon breeder tank also the megaray did not warm the basking area enough and I had to use another halogen light which really seemed to confuse the poor thing. What is your take on this. He also did not want to bask with the megaray. Thankyou Gena

    • avatar

      Hello Gena,

      I do not have figures on that bulb….hoping to check soon, or will contact the company.

      A halogen paired with a megaray should not cause avoidance or confusion; similar pairings are very common, and work well. Could the megaray have been too close to the basking site…I haven’t checked the specs, but I believe there are minimum distances recommended (in order to avoid eye damage); perhaps the lizard was uncomfortable due to this? Best, Frank

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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