> On 7/20/08 7:40 AM, "drache613" wrote:
>
> >
> > I had a quick question. I recently had a friend on the forum who
has
> > been using the Zoomed Powersun on all of her dragons, with no
> > problems at all.
> > Well, recently, one of her dragons began acting strangely. She
> > attributed it to something else, started doing supportive care,
etc.
> > The vet could not find anything wrong with him.
> > She had noticed some black specks floating around in the light,
but
> > did not think anything of it.
> > However, over the course of a couple of weeks, he got worse & then
> > passed away. She took him back to the vet & he diagnosed him with
> > radiation poisoning. Can you believe that? Now I personally
cannot
> > confirm it was emitting UVC, but based on what the vet said this
is
> > what it sounds like happened.
> > Can a bulb all of the sudden burst & go bad that quickly?
> > Has anyone heard of this before from these lights? This is the
first
> > time that I ever had but thought I would ask people here.
Perhaps it
> > was just a fluke or a bad bulb? She is going to be contacting the
> > company to talk to them.
> > If anyone has any feedback that would be great.
> > Thanks.
> >
> > Tracie

Hi, Tracie.

No need to panic about this... I don’t like to criticize a colleague,
but there are times when there seems no alternative. The dragon
surely could not have died from "radiation poisoning" ... for several
very good reasons.

ZooMed Powersuns, like all properly made mercury vapor lamps,
cannot "burst and go bad" nor can they leak UVC.
The arc tube in which the mercury vapour is sealed will only operate
as long as it is intact. If it cracked or broke, the arc won’t light
and there is no UVC, ...LOL, there is no light at all, it is a dead
lamp.

On the other hand, if the arc tube was undamaged and was working
fine, but the outer glass - the "bulb" - cracked or broke, the
filament part of the bulb would immediately pop and this breaks the
circuit, of course, and the arc tube goes out and there is no UVC, no
light at all, ...again it is a dead lamp.

(If it was an EB lamp, by the way, you might think the arc tube could
go on burning... but it can’t, because these have little "filaments"
called burn fuses, they don’t ballast the lamp, but they pop
immediately, in the same way, if there is a crack and air gets into
the lamp...)

What if the coating on the inside of the lamp was imperfect? Kerry
has suggested it might have "come loose", but it is a spray coating
so that isn’t very likely... and in addition, I might be wrong on
this one, but I don’t think it is a phosphor coating, like that found
on fluorescent tubes, which absorbs UVC and turns it into visible
light; certainly there is no obvious "phosphor" signature in the
spectrum, which looks like 100% mercury vapour light.
I think the coating is merely a diffuser, like a fine paint spray,
turning a spot-type lamp into a flood, and reducing the UVB in the
process.
What is preventing UVC from being emitted, then, is the nature of the
glass itself... the typical glass used for mercury vapour lamps is of
a type that blocks all UVC and blocks a little of the UVB, too, in
fact. So I don’t think this lamp would be capable of emitting UVC,
even if there was no white coating at all.

ZooMed Powersuns don’t emit a great deal of UVB, either, in fact...
the manufacturers themselves say the lamps emit the equivalent
of "the noonday sun in the shade" (quote from leaflet). You aren’t
going to get "radiation poisoning" from that.

I reckon the black specks are little bits of metal which have
spluttered off the tungsten filament. I’ve got quite a few of these
in my oldest lamps on test, including a 3-year-old MegaRay SB.
Eventually the filament loses so much tungsten that it is too thin
and breaks, and that’s the way it dies of old age.....

....so...

this Powersun, how old was it? Could this dragon have developed MBD
and died from a lack of radiation, rather than the opposite?

What were the symptoms of this poor dragon’s "radiation poisoning"?
Photo-kerato-conjunctivitis - eyes closed, eyelids swelling, and a
miserable dragon hiding in a corner - would be the first thing I
think I’d expect to see in a beardie, if a lamp was emitting anything
nasty. Skin "burns" and blisters might follow...

I’m so sorry he died, but I really think it was unlikely to be UVC
from the lamp.
If she is convinced there was a problem with it, she needs to have it
tested - a quick look with a UVB and a UVC meter should be all she
needs to have done.
I’m sorry for her loss.

All the best,

Frances

Posted by: "" bmaccargar
Sun Jul 20, 2008 10:12 am (PDT)
What Frances said here is on the spot 100%. There is no way that the animal
died from radiation poisoning from the PowerSun but lack of UVB is much more
likely if it was indeed a UV related incident at all but still not likely
unless the dragon was gravid. Now if they were using the ZooMed compact
fluorescent that would be a different story.

We are always sorry to hear about anyone loosing there dear pets. Hopefully
a necropsy was done to help understand what happened.

Best Regards,
BobMacCargar

and would the deep dome keep it far enough away from the screen to keep the screen from burning?