(part 4)
continued:
Most self-ballasted (SB) MV lamps suffer from a 50% failure rate over the first month and a 70%-80% decay rate in total UV-B emitted during its life (Westron’s new MV lamps have decreased these percentages to 30-50% total decay). One of the best-selling style MV bulb (ZooMed), the 160 watt FLOOD, emits much less UV-B than stated on their endorsements after decay. These bulbs settle in at about 12-15 µW/cm2 at 12". Why, then, do we see such incredible results with MV lamps when compared to fluorescents? After all, two high-quality fluorescents will produce 25–30 µW/cm2 at 12". The answer is simple: MV lamps emit less total UV-B than fluorescents — but more “usable” UV. Studies have shown that MV lamps produce the same percentages of D-UV (and UV-A, which is another subject) as a percent of total energy emitted as the sun.
Self-ballasted SPOT-style lamps produced much higher UV readings than any other reptile bulb on the market until the Westron Mega-Ray Flood lamps were marketed this year. The Spot lamps still are subject to the failure rates of most self-ballasted MV lamps. These lamps settle in at about 100–150 µW/cm2 (at 12"), but have a much narrower disbursements of UV-B. Dr Gehrmanns recent paper proved that the narrow spot would raise the blood hydroxyl levels to that in nature; there fore the entire animal does not need to be immersed in UVR to stay healthy. These are excellent rehabilitation bulbs for severe metabolic bone diseases (MBD). Regarding concerns that iguanas under this style of lamp will need “goggles” to prevent blindness from “excessive” UV exposure, remember the exposure levels in their natural environment. We have five iguanas that have spent 3 years exclusively under mercury vapor SPOT lamps with no negative impact on vision. However, the distance from any MV lamp to the basking area must be regulated in order to provide optimum temperatures, regardless of any distances stated by the distributor!
So, what is best for iguanas? I recommend 75-150µW/cm2 at 12" for 6-10 hours per day (comparable to minimal natural exposures in the wild). The best way to realize this number is to use an ultraviolet radiometer (such as the Solar Meter 6.2 hand-held version; see references) to measure the amount of UV-B available to your iguana.
To achieve these levels of UVB you can use 100 and 160-watt T-Rex UV Heat SPOT lamps will emit 75–150 µW/cm2 (at 12” after break-in) — as long as they burn. The Westron Lighting Mega-Ray 60-watt in-line ballast MV lamps and the Mega-Ray SB 100 and 160wt mercury vapor lamps will produce 150-300µW/cm2at 12” (The new Mega-Ray 60-watt in-line ballasted MV lamp from Westron Lighting produces excellent UV-B with very little decay and without the problem of failure, no self-ballast to fail). No other supplemental UV-B source is necessary with these lamps.
The ZooMed 5.0 fluorescent lamps are at the top of the ladder in terms of meeting these specific requirements (i.e., the best “usable” UV-B) but other tubes are now available that perform well such as Hagen 8.0 line and the Arcadia 5.0. Use at least two of these lamps with reflectors to achieve the desired exposure levels. These lamps will also need to be closer then 12” (8-10 inches) to reach the desired UVB level. Generally speaking, reptile fluorescent tubes do not have a very good light quality and some form of “full spectrum” lighting should be used in conjunction with them.
The 100- or 160-watt T-Rex FLOOD lamps* or the 160 watt ZooMed FLOOD
(continued)
lamp also may be used in conjunction with ZooMed 5.0 fluorescent tubes or other quality fluorescent tubes.
*T-Rex will soon be using a Mega-Ray design for there FLOOD lamps and will not need the security of additional fluorescent tubes to reach the proper UVB level.
The market is being flooded with mercury vapor lamps mostly manufactured in China as well as poor quality florescent tubes. These have preformed poorly in our tests and we do not recommend using them unless you have an ultraviolet radiometer to measure the UVB levels. Some of these lamps have had enormous and unsafe levels of UVR while others have little to no UVB. Please do not be “sold” on inexpensive pricing or fancy packaging. Please keep in mind that any lamp sold for human commercial lighting such as the VitaLite full spectrum fluorescent tube is not capable of producing enough UVR to keep iguanas or other high UVB dependent reptiles healthy.
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Robert MacCargar is the founder and President of Mac Industries (
http://www.reptileuv.com/) and a wonderful reptile rehabilitator and herpetocultralist. He currently designs and creates the very best bulbs on the market and well as constantly adding new data to his research accomplishments on UVB and light in magazines and at the UVB METER owners at yahoo (
http://groups.yahoo.com/group/UVB_Me...yguid=99475151).
He is one the web's wonders and he never ever stops amazing me with his clever and knowledgable mind.
