HQI & U/V ray Shielding

[Ltspd]

Lets discuss this some more.

P.S. - Don't forget that you cannot blow air directly across an exposed double-ended HQI lamp because these

I have (2) fans in the hood, one blows in the other out. The fans are on the left/right of the bulb at each end. I have attached a shot of the hood upside down when I first set things up. This is for the 6500k's. Do you see any problems wiht the way the air will flow and the lights themselves?

[Ltspd]

I have heard people mention that some of the picture framing glass which have UV coatings to protect the pictures might be a good option to try for a DIY setup as well.

Anyone know anthing about this stuff? I may have to visit a framing shop and see if they can provide some further information.

[scubadude]

WoW! this thread is getting intense!....I just wanted to know what type of shielding to use!!

Ok the glass made for Ninongs canopy is made by the Co. SCHOTT and it is as Ninong said the type DURAX here is a link

http://www.us.schott.com/english/com...es/canada.html

Now im not sure how its all categorized and the one thing we ARE lacking is test for UV-C, as said above UV-A is not much of a concern, and we have test for UV-B, Im just gonna have to assume that we are blocking out approximately the same values of UV-C as we are the UV-B? If you look at the SCHOTT link above you will notice that There is a Borosilicate type glass.....this has also been brought up as a good possible UV filtering glass....Now that Ninong has said that we cannot have fans blowing on our bulbs that just puts another monkey wrench into the pot, but I think I can deal with it, Just put the fans under the sheilding.

[Ltspd]

I didnt see anything special about the Durax, it says its tempared float glass. Float glass from what I understand is regualar green glass.......

I will call them monday.

I too am curious about the fan issue, I dont want 3 hot bulbs in a wood canopy, can you say FIRE.

[scubadude]

Originally posted by Ltspd
I didnt see anything special about the Durax, it says its tempared float glass. Float glass from what I understand is regualar green glass

Actually "Green Glass" has some really good quality's at shielding the bad UV's from the link Ninong has presented!

Ninong, can you tell me if your shield has a slight green opaque tint to it? Have you turned the light on and seen the color that the light fixture produces? Any chance you can give us a pic or two?

[Ninong]

Ltspd,

According to information provided by one of the respected members of reefs.org (who owns an LFS in NH) that I linked to in the many threads I cited above, regular mogul based Iwasaki lamps burn at a temperature of 1350 degrees F for the internal bulb and 350 degrees F for the outer quartz glass envelope. According to this same individual, the HQI double-ended lamps burn at 3000 degrees F. According to him, these lamps are negatively impacted by air blowing directly on the exposed HQI double-ended lamps because if you reduce the operating temperature of the lamp it will negatively effect the color and lifespan. I have read this same advice concerning these lamps in the literature. I have not come across anything to suggest that this is a problem with regular mogul base lamps.

You should have no problems with "fire" in your wood canopy provided you properly install your lamps, no matter what kind of lamps you choose. Just be sure to use spacers that leave at least 3/4" space between the sockets and the hood itself, and, of course, reflectors.


Scubadude,

The "safety glass" shield on my Aquastarlight Future fixture is perfectly crystal clear with no tint of any kind. "Safety glass" is what AB-Aqualine calls it in their catalogue. I'm sure it has the appropriate UV-absorbing qualities in addition to providing protection against exploding lamps. Sorry, but I have no pics. Susan has the exact same fixture over her tank (same color, same size, same everything). She has posted pics in the past. The color of the light from the fixture appears to be a beautiful crystal clear white to me but that's just looking at it in a darkened room, not over a tank of water. If you search the lighting archives you might find some of the pics that have been posted. One of the other members posted some nice pics of his Aquaspacelight fixture (practically the same thing).

Thanks for finding the Schott-Durax site. I will have to check it out. I was going to look for it last night but I got tired looking up all the Reef Central threads that contained information on this topic. Never did find the one particular thread I was looking for, but I know it's there somewhere on one of the boards.

If you or Paul haven't yet done so, you should really check out the threads that I linked. One of them contains a very scary warning from a hobbyist who installed 250w 10,000K HQI double-ended lamps in his hood without protective shielding and awoke the next morning thinking he was permanently blinded. Evidentally the tank was in his bedroom. He had serious medical complications from exposure to the unshielded light from these lamps.

IMHO, you should always use protective shielding with HQI double-ended lamps.

Regards,

Ninong

[scubadude]

Really that info that you have provided has literally saved me lots of time and $$ I think I will install a couple of blinds over my tank for non viewing time since I will be in my office which will be literally 3' from the bulbs! and when viewing time comes I just pull the blinds.

The things I do for this hobby

[SPasse]

Hi All,

I will not weight in on this aspect of HQI lamps, except to say that that I would personally use a UV/splash shield on the lamps, for UV emission reasons alone.

But another things to consider are the physical/electrical reasons why (especially) these kinds of lamps should be shielded.

1 Electrical. The contacts on these kinds of bulbs and the mating sockets are not designed for salt air, i.e. corrosive environments. As an electrical engineer, I would rate the potential for contact failure and/or possible fire hazard high if these contacts were subjected to direct salt air exposure. This is especially a problem in enclosed hoods where condensation is much more pronounced. When I say “enclosed hood” I am not talking about an enclosed fixture. Chain suspended enclosed fixtures like for example an IceCap fixture, suspended over an open top tank, are about the best solution from an “Isolation from the elements” point of view.

2 Salt/mineral deposits on the glass envelope of the lamp. I have seen a number of light fixtures without glass or Plexiglas shielding where the lamps were discolored and coated with mineral deposits due to “salt air” exposure. Because of the temperature of the lamp envelope, deposits are “mineralized” and are much more difficult (If not impossible) to remove by cleaning. The owners of these fixtures claimed that they were religious about cleaning them.

3 And as mentioned above, an illuminated HQI lamp will instantly explode with when subjected to even a tiny splash of tank water. I might also mention that these bulbs contain mercury and other “toxic” substances that I certainly would not want expose a reef tank to.

Regards,

Scott Passe

[Ninong]

Sanjay Joshi was kind enough to respond to this question here: http://www.reefcentral.com/vbulletin...814#post255814

Ninong