I think all of the major manufacturers have corrected their issues with CFLS now.
Testing with a solarmeter 6.2 & 6.5 and checking the readings on newly manufactured* zoo med, exo and zilla cfls give pretty much what is expected for readings.
If a cfl
that is producing the correct wavelengths of UV light is used at the correct distance, then there is no difference than using a linear tube.... in any particular spot.
*One problem is that there is allot of new old stock still up on eBay and on pet store shelves that some folks just don't want to take a loss on. (That goes for questionable brand linear bulbs as well.)
There is
who knows how many thousands++ of dollars worth of "new in box" old model cfls still out there that were manufactured a few years ago ....potentially leaking excess low range uvb and c rays.... that people are trying to dump.
Anyone thinking about getting a good deal on certain brand CFLs off eBay should think twice. (again...that goes for questionable brand linear bulbs as well.)
This does bring up another point when talking about UV and reptiles.
Serious hobbyist have Solarmeters.
Or at least will borrow a friends regularly to take readings of their set up(s).
And before anyone tries to call me out for saying that just because I sell them, let me remind you
I sell them because I am a serious herp hobbyist.
I have 5 Repti Sun 5.0 CFLS screwed in and lit right now over sensitive dart frog set ups... that have been set up that way for almost 3 years.
The set-ups have been reflector/distance/uW/cm2 callibrated with Solarmeter 6.2 and more recently, rechecked with a 6.5 to get UV index reading.
Plus, I must point out, all cages have some reduced UV and "UV free"zones.... as you would find in Nature.
Anyway, hope this helps.
Cheers,
Todd