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Thread: UVB lighting quick info

  1. #1
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    Default UVB lighting quick info

    I know info gets lost in the search mode, and sometimes stickies aren't obvious. Since tegus are coming out of hibernation and basking regularly, it is a good time to change UVB if needed or redo an enclosure that maybe needs an improvement or two. i posted this quick message somewhere else and just thought it might make good food for thought here, too. Not my info, but from Dr. Frances Baines.

    About tube lights:
    "Tubes supply a diffuse "glow" with low intensity visible light, very little heat, and a fairly uniform UVB gradient, resembling natural UVB "in the shade" on a sunny day."

    "Since they are not particularly bright light sources, fluorescent tubes can be situated directly above a reptile at fairly close range without, apparently, causing distressing glare. However, some do emit high UVB at close range and traces of UVC (1-3 uW/cm²) can be detected at the surface of all tubes tested, hence a safe minimum distance of maybe 3 - 4 inches would seem advisable.

    The diffuse glow from a fluorescent tube is not focused into a beam, and hence does not project a great distance from the lamp. To achieve UVB coverage over a wide area, it is advisable to use the longest tube which will comfortably fit inside the vivarium. Reflectors may be used to direct the beam further into the vivarium and increase the effective output, for species with higher UVB requirements."

    About compact/coiled:
    "UVB compact fluorescent lamps also produce diffuse, low levels of UVB at basking distances. However, at close range and/or if reflectors are used, the light and UVB may be intense, making good positioning difficult. These lamps decay more rapidly than tubes and may need replacement after six months.

    A few brands of fluorescent lamps for reptiles, both compact and tube types, have been found to emit hazardous shortwave UVB. These have caused eye problems such as photokeratoconjunctivitis. Some manufacturers that experienced the problem say they have addressed the issue, while others are still addressing it. However, if your reptile develops swollen eyes or refuses to open them shortly after a new lamp is installed, see your herp veterinarian immediately. You may wish to refer him or her to this article. Lamp placement, the lamp itself and/or other factors could be responsible."

    About Mercury Vapor:
    "Mercury vapor lamps vary in quality and UVB output. These lamps also produce significant heat, and they cannot be thermostatically controlled, so they are most suitable for large enclosures. Be sure to follow the manufacturer’s guidelines and instructions for proper lamp placement and distances. Several mercury-vapor-lamp types are available. Inexpensive spot lamps with clear-glass faces may produce extremely narrow, hazardous beams of intense UV light and are best avoided. Flood lamps have much wider beams, and they are ideal for reptiles that naturally bask in the sun. They create directly below the lamp a zone of bright light and UVB resembling a small patch of sunlight. Brands vary in their UV Index. Recordings range from about 2.0 (full tropical sun before 8:30 a.m.) to 7.0 (full tropical sun between 9 a.m. and 10 a.m.) within the basking area"

    Quotes From:
    "FRANCES M. BAINES, M.A., VetMB, MRCVS, is a veterinarian researching the requirements of reptiles for visible and ultraviolet light. She writes on uvguide.co.uk and, with colleague Andrew Beveridge, independently assesses reptile lamps worldwide. She is currently an advisor to the Reptile and Amphibian Working Group of the British and Irish Association of Zoos and Aquariums."


    Laura R (FL)
    1.0.0 Colombian Tegu
    1.4.0 Argentine B&W Tegu
    1.2.0 Red Tegu
    1.2.0 B/WxRed Tegu
    1.0.0 Green Ameiva (yet another teiid)
    7 other lizards
    1 little gator
    3 FL box turtle
    1 Sulcata tortoise
    16 snakes
    5 fuzzy pets
    4 little frogs
    a bunch of creepy bugs
    and a partridge in a pear tree

  2. #2
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    Thank you for the great info Laura. It would be good if you would make this a sticky post. So later on when we are looking for it it's easier to find it.
    Rich is not how much you have, or where you are going, or what you are.Rich is who you have beside you.

    Our videos :

    http://www.youtube.com/user/txrepgirl

  3. #3

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    I came just in time I was actually in the mix of finding new bulb setups. My question

    Which is best/ what is the difference between long tube zoo med repti-sun 10.0 uvb bulb, mercury vapor bulb, and the powersun uvb bulb.

    Each puts out uvb but only the tube style tells the amount of uvb it puts out. Whats the benefit of the mecury vapor bulb other than being cheaper than the powersun bulb. I would like the info to know which route would be best/ emit more uvb/ the necessary level. Thanks in advance

  4. #4
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    Lighting isn't always as straightforward as the labels say.

    "It would appear that both the ReptiGlo 10.0 and the ReptiGlo 5.0 use exactly the same UV-emitting phosphor, in almost the same quantities. The two 26-watt lamps, and the two 13-watt lamps are similar in their output as well as having the same UV spectrum. This seems curious, since one might reasonably expect a 10.0 lamp to be emitting approximately twice as much UVB as a 5.0 lamp. Although it is not specifically stated anywhere in the ExoTerra literature, traditionally, 10.0 and 5.0 have been understood to mean UVB at a level of 10% and 5% of total output, where the total output is (UVB + UVA + visible light).
    Analysis of the spectral data is very revealing, however.

    The 5.0 lamps are both emitting 3.7% UVB as a percentage of the total output.
    The 10.0 lamps are emitting 8.6% and 6.0% UVB.
    The reason for this is certainly not because the 10.0 lamps emit more UVB than the 5.0 of the same wattage. (In fact, the 13-watt ReptiGlo 5.0 lamp is emitting slightly more UVB than its 10.0 counterpart.) It is simply because the visible light output from the 10.0 lamps has been lowered, therefore increasing the percentage of the total which is contributed by the UVB."

    Tubes:
    "The only way to really tell if these are producing any useable UVB is to have a spectrogragh done. The % attached to the bulb, 2%, 5%, 7%, is suppose to be the percentage of UVB as a comparison of total iridescence emitted. . Without knowing what the total iridescence is, the percentage means nothing. Even more importantly is the fact that the UVB in fluorescents is very sensitive to the quality and quaintly of phosphor in the tube along with other ingredients."

    Mercury vapor( From Bob Mac):
    "MV bulbs produce 3 times more UVB in the 290-300 (D-UV) nanometer range than “tube” type UVB bulbs of the total UVB out-put. 10uW/cm2@12’ from a MV FLOOD lamp is equivalent to 30uW/cm2 from a tube lamp. This fact helps explain why every rehabilitator I have spoken to sees a remarkable difference in the effects of MV lamps over tubes even though they may be using MV FLOOD lamps that are only emitting 10-15uW/cm2."

    A ZooMed PowerSun is a type of MercuryVapor bulb. It is the one I prefer to use.
    Laura R (FL)
    1.0.0 Colombian Tegu
    1.4.0 Argentine B&W Tegu
    1.2.0 Red Tegu
    1.2.0 B/WxRed Tegu
    1.0.0 Green Ameiva (yet another teiid)
    7 other lizards
    1 little gator
    3 FL box turtle
    1 Sulcata tortoise
    16 snakes
    5 fuzzy pets
    4 little frogs
    a bunch of creepy bugs
    and a partridge in a pear tree

  5. #5
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    I have been using the ZooMed Power sun for years now and I love them. I like it that it's baskin, UVA/UVB light all in one.
    Rich is not how much you have, or where you are going, or what you are.Rich is who you have beside you.

    Our videos :

    http://www.youtube.com/user/txrepgirl

  6. #6

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    Thanks for the help/great info guys!

  7. #7
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    While overall most of that information is very good and accurate, there is the odd bit that is extremely misleading. It really goes to show that not all vets are experts or fully understand that which they are talking about. The statement '10uW/cm2@12’ from a MV FLOOD lamp is equivalent to 30uW/cm2' from a tube lamp is a fine example of such. The measurements are both given in intensity, so how is 10=30 ? This makes little sense, no matter how one tries to dissect it. At first I thought maybe the vet was talking about the heat component and how this would facilitate cholecalciferol production, but there's going to be next to no heat from a MV flood at 12 feet. As always, read anything with skepticism and think about the information being presented.

  8. #8
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    It does make sense when you factor in the most effective wavelength of UVB and not focus on the equivalent units as much.
    Laura R (FL)
    1.0.0 Colombian Tegu
    1.4.0 Argentine B&W Tegu
    1.2.0 Red Tegu
    1.2.0 B/WxRed Tegu
    1.0.0 Green Ameiva (yet another teiid)
    7 other lizards
    1 little gator
    3 FL box turtle
    1 Sulcata tortoise
    16 snakes
    5 fuzzy pets
    4 little frogs
    a bunch of creepy bugs
    and a partridge in a pear tree

  9. #9
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    Not really, no. For what you're talking about, that would mean the MV bulb would have to have an acute peak at around 297nm wavelength (if I remember correctly, this is approximately THE most efficient wavelength for Vit.D3 production), while the fluorescent tubes would have to have an acute depression at the same wavelengths. I've never seen any bulb's spectrogram present such a profile (or to put it differently, if there were ANY bulb with an accute peak at 297nm, it would so outperform all other bulbs as to make them pointless; as is, these bulbs just generally produce UVB in the ranges necessary - LEDs, however, can be that focal, but then you're talking about $300 wholesale price per LED, not exactly cost effective at the moment for the average consumer). Likewise, the response of the photoreaction to UVB also presents as a rounded parabola, not an acute peak reaction rate. So while 297nm is the most optimal, 295nm and 300nm don't drop off to 40% in comparison, at most they drop off to about 90%. The further away you move from optimal, the further the drop in reaction rate/production, no matter what the source is. However, as stated, what is presented by the author is the intensity of the bulbs. If all other variables are equal (as they should be in such a statement), then there's literally almost no way a 10uw/cm^2 is going to outperform a 30uw/cm^2 source. It's basically the same as saying my car travelling at 10miles/hr is faster than your car travelling at 30miles/hr because I'm driving a Honda and you are driving a Saturn. It makes no sense. In a photoreaction (basic physics&chemistry), the variables that will affect the reaction rate are 1) intensity of the wavelengths involved, 2)temperature of the component chemicals, 3)concentration of the reactants and 4)concentration of the products (there are others, but less important). 3&4 are completely independent of the bulbs, so if there is such a measured difference, it's because of the reptiles involved, not the bulbs. 2 CAN be a function of the bulb, in how much heat it throws out to warm up the reptile: at 2' this would likely be considerable, at 12' I find this to be a huge stretch of the imagination. Nevertheless, to make the claim that it is the bulb that is more effective when you're measure one reptile at 35C and another at 13C is immensely misleading.

    Don't get me wrong, usually MV bulbs are of greater intensity, and with the heat, I too agree they are a better option in many cases. However the statement in question is patently false without some greater description to explain the discrepancy with basic physics.

  10. #10
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    I'll have to go back to the original article when I have more computer time later on. I don't have all the info in front of me, but I thought I recall that the MVB did peak where the tubes depressed, hence the statement that MVB produce three times more in the 290-300nm (D-UV) range than tubes. (he says that above). Maybe his logic is just wonky when he tries to extrapolate the data out to say MVB is three times as powerful, hence 10uW/cm2@12’ from a MV FLOOD lamp is equivalent to 30uW/cm2 from a tube lamp. But you know, I get what he is trying to say. It may be that I am reading it on layman's terms, lol.

    I was also wondering if he meant 12" rather than 12'. Who puts their UVB at 12" anyway? I also wanted to note that this info came from BobMac from MegaRay and not from Dr. Frances.
    Laura R (FL)
    1.0.0 Colombian Tegu
    1.4.0 Argentine B&W Tegu
    1.2.0 Red Tegu
    1.2.0 B/WxRed Tegu
    1.0.0 Green Ameiva (yet another teiid)
    7 other lizards
    1 little gator
    3 FL box turtle
    1 Sulcata tortoise
    16 snakes
    5 fuzzy pets
    4 little frogs
    a bunch of creepy bugs
    and a partridge in a pear tree

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