CFL UVB questions

[Sdaggan]

I don't have a tortoise yet, but am doing research.

I've noticed a lot of people don't like CFL UVB lights for torts, and was wondering why? I've used CFL on my other reptiles (beardies, blue-tongue, anoles, water dragon, and red-eared slider) for years without any issues. I make sure to replace them every 6 months like clockwork. Is there a reason they would not work well for torts? The only thing I can think of is that tort enclosures are larger, so a tube would cover more ground vs the CFL. Thanks for any thoughts!

P.S. My future tort will have outdoor time, but it gets cold where I live, so I would need to keep it indoors part of the year.

 

[dmmj]

A lot of people on the forum over the years
have had serious issues leading up to blindness with those type of bulbs. Does it happens every single person? No but we generally recommend to not use those bulbs.

 

[Sdaggan]

I was looking through some previous threads and saw Yvonne G state that they only caused issues in baby torts and not the adults. Is that true?

Also, I only use the lowest wattage CFL UVB bulbs (I don't rely on them for any light or heat, I use basking heat bulbs for that). I saw some people saying that the higher wattage lights tend to cause more issues.

I personally don't like MVBs because I had a beardie that had major issues when I used one, not because of the expense or anything.

Not trying to be difficult or defend CFLs or anything, just want to get as much info as I can to make the right decision. As of right now I'm leaning towards a long tube UVB (once again I'm not a fan of MVB).

 

[Kapidolo Farms]

I think aside from other concerns they are to spot bright specific. Two sources of light that are the same yet different by local intensity might make this make sense.

1) a 24 watt CFL emits light from about a two inch diameter coil, all more or less focused onto one place in the enclosure.

2) a 24 watt T5 HO (similar length of tube but not coiled, the same wattage as well) shines the same "volume" of light over an area that is 22 inches long.

They both put out the same amount of light but the straight tube disperses it over a bigger area.

Another consideration is the the CFL has as cheap a ballast as possible, it's a throw away part of the CFL. The e-ballast in the straight tube fixture is meant to run at least four or five tubes if not more, it's higher quality and does not create as much WiFi interference etc.

And there is all the anecdotal reports of blinding.

 

[Markw84]

I was looking through some previous threads and saw Yvonne G state that they only caused issues in baby torts and not the adults. Is that true?

Also, I only use the lowest wattage CFL UVB bulbs (I don't rely on them for any light or heat, I use basking heat bulbs for that). I saw some people saying that the higher wattage lights tend to cause more issues.

I personally don't like MVBs because I had a beardie that had major issues when I used one, not because of the expense or anything.

Not trying to be difficult or defend CFLs or anything, just want to get as much info as I can to make the right decision. As of right now I'm leaning towards a long tube UVB (once again I'm not a fan of MVB).

There definitely was a problem with some of these bulbs 10 years ago or so when the manufacturers were working with best ways to provide artificial sources of UVB. Since UVB is blocked by glass, quartz or other crystals must be used for the bulb - expensive. It is the types and combination of the phosphors coating the inside of the tube that filters and allows the desired wavelengths to be emitted. This formula had been a work in process for some time. Some of the early bulbs gave out actual UVC wavelengths which indeed are harmful. They had to change their manufacturing techniques and correct, which they did. However, older bulbs were not recalled, and since many were in pet shops who may have inventory sit on shelves for years, or don't rotate inventory properly, we saw some of these older bulbs create problems several years after they stopped manufacturing them that way. Those who had tortoises injured and even blinded by one of those type bulbs had horrible situations which led to a real and understandable mistrust and caution against using them.

Any type of UVB bulb can cause eye damage if mounted improperly. It is important to get the correct distance and have the light coming from above the tortoise, not the side. If the tortoise can get too close, it will create that same issue as snow blindness, and if persists, can get serious. So it is important to get the right distance depending upon the type and strength of the bulb you choose no matter what type. That is why I always recommend using a UV meter to be sure the UVB you are providing is correct, and when the bulb would need to be replaced. UVB is potentially dangerous. I cannot imagine blindly using any UVB source without knowing what it was actually producing at the placement I have chosen.

I use many compact bulbs for my aquatic turtle enclosures because of the small area of brighter emission. I get great results and find they last normally around 18 - 24 months before I need to replace. I do not use compacts for my tortoises, though. Not because I believe the ones they manufacture now are harmful, but because they give out relatively low amounts of UVB for what I want for tortoises, and it is in a very small circle of effective area, as @Will mentions above. I want a larger area of effectiveness for tortoises as they often bask indirectly, not just under the basking spot. I like the high output long tubes as it give a bright daylight lighting that I use for "midday sun" in my enclosures.

So I am with you on the choice of long tubes. I think they are the best solution for our tortoises, especially in closed chambers.

 

[Sdaggan]

Thanks for all the info! I love how informed and helpful the reptile community is!