Howdy All,
At the beginning of the controversy over the use of compact fluorescent (CF) UVB sources, keepers who were already successfully using the ZooMed Reptisun 5.0 CF wondered what all of the fuss was about. They, like you, had been using them for years with no noticeable negative effects.
If I remember the timeline and issues correctly, reports came first regarding the ZooMed Reptisun
10.0 CF causing photo-kerato-conjunctivitis (snow blindness) and to a lesser extent the 5.0 CF too. Because there are not very many actual
manufacturers of UVB CFs, all
non-brand names may need to be considered suspect of having the same flaws in their phosphor design too. In addition to having a phosphor that shifts the UVB spectrum in the wrong direction making them more
biologically active (able to cause
short term and
long term damage) than
normal sunlight, their compactness increases the intensity; measured in uW/cm2, of the UVB making the effects even more of a concern.
So back to why are there chameleons who don't have any noticeable effects from these suspect CFs? Most importantly is how close and how long they bask under these CFs. There is a far greater likelihood of injury if they are able to get within a few inches or less rather than 12 inches away or farther. The UVB intensity increases somewhat exponentially (square law) with decreased distance. At the surface of these tubes, UVB levels can reach 1000uW/cm2 rather than the typical 20-50uW/cm2 found at 6"-12" away that is often called out for chameleons. Linear (vs. CF) tubes spread their UVB energy out over a wider basking area so they tend not to have as much of an issue at closer distances (no UVB "hot spot").
But what about the shifted UVB spectral content of the suspect CFs? That issue is also reduced by increasing the distance.
The age of a chameleon is likely to have a big factor as to whether or not a problem will present itself with the use of CFs. Chameleons that are 0-6 months are much more susceptible than ones that are several years old. Combine the age sensitivity with the fact that these very young (babies) chameleons are more likely to be housed in much smaller enclosures where the CF is often placed directly on top of the screen means that they will be hit with a double-whammy. With a baby in a small enclosure and the CF in an aluminum reflector and you might as well break out the BBQ instead
.
It boils down to: It is possible to use a CF in the right situation and not cause damage to a chameleon. Using a CF narrows the "Success Window" for keeping a chameleon thriving vs. surviving. This is especially true for new keepers with very young chameleons who are not aware of these details and often find out too late. The negative action (overreaction?) of the forum members to using CFs in favor of linear UVBs has probably saved many chameleons from injuries caused by the misuse of CFs. Other than its inherit compactness, there isn't much of a reason to recommend CFs over linears for chameleon applications.
The "safe bet" has been the ZooMed Reptisun 5.0 linear tube because its phosphor recipe is effective at producing the desired UVB while not producing any of the "out-of-band" UVB that causes the health concerns previously mentioned. Combine that with often being able to buy them on sale for as low as $14, in any length, from
www.lllreptile.com and
www.bigappleherp.com, makes them a good choice.
A final note: I have spoken with ZooMed representatives and they are keenly aware of the situation and are working on corrective actions regarding the phosphor in the CFs. Their linear tubes are made by their manufacturer in Germany vs. the CFs being made in China. If and when they get the phosphor formula straightened-out or get the CFs mfr'd by the German site using the good phosphor, then we can re-evaluate using their CFs in our application
.
(Don't get me started on the early (death-ray) R-Zilla 25 and 50 series linear tubes
.)
weird huh?
