Lenses keep popping on MH light

[astranotus]

I have a 3x250w DE MH light fixture that is 85" long..and have been having problems with the lenses popping and falling into my display...had 1 pop on the outside but the middle one has popped 5 times on me....last night the most recent ..the lights went out and 20min. later it popped while I was watching TV...Has anyone had this problem or know what may be the cause of this??/ I am at a loss here..just doen't make sense that it is always the same one and has happened 5 times...they are tempered and are the lenses made to be under the MH bulbs for UV protection...Any ideas would be helpful...

 

[JayM]

are they falling out, or shattering :: ?

 

[Doherty]

Never heard of this personaly but possible.
The MH lampsget extremlly hot..... With the heat will cause the glass lense to expand to some degree...... and contract with cooling. Depending on how tightly the glass lense is secured to the fixture....... Sounds like it is possible that the glass was cooled too fast after the lamp turned off (possibly a very cool room... Don't know) and cracked...... But who knows....... But for this to happen so many times on the same fixture, this is a possibility.

How it the glass secured to the fixture....... Is it very tight when in place?

 

[astranotus]

They are loose and have space between them as well...see I have a 85" light and they slide in like a plastic splash guard would on a current light fixture...just that mine...come in sections...So i put a plastic piece in then the glass piece..that goes right under the bulb...then where there is no bulb..the next piece goes in..plastic...then a bulb is there and glass goes in..etc...but I can physically move it back and forth and side to side...BUT...I too was thinking that it may have cooled to quick....there is a high window..but..it happens when the lights are on...even happened one morning when I got up and was on my way outside for a smoke before the lights went on (timer).and just as I walked passed the tank (on a cement floor)...POP..it broke...there is no pattern...

 

[MofoCorals]

I had that happen twice to me three days ago when I moved in. Im not sure why though. Its been fine since. I think it was that I brought the glass from outside an installed it right away. But like I said Im not sure.

 

[willray]

Can you sight down the length of the light?Look for any distortion,bowing....I'm thinking something may have let go and the fixture or where the lens slide in has widened.

 

[MofoCorals]

I'm still having this problem. It just piped on me and by the time I checked it my corals were foaming. That can I do to fix this?

 

[Spaceman]

Foaming????

 

[MofoCorals]

They are throwing slime, clear thing

 

[astranotus]

There is good space for the lenses..it's not tight in the slots and if too wide how would that make it pop?...Weirdest thing..it happens at different times and different circumstances..right now it is good...but in like a few months or even 5-6..it will happen again..well at least from past experience with this light....proper lenses..and new..I wear gloves when handle etc....though maybe a surge in the middle light somehow pops them?...just baffled...
Elmafioso52988...when this happens...pick out all the glass from the DT and don't run that light until you get a new lense in there...the UV can burn the corals and they will slime..

 

[Joel A]

is the glass tempered?

 

[Joel A]

sorry, just re read your post and saw that you said it is.

Sounds like its some sort of heat issue.

 

[Cheetos]

How close is your light to the water? Possibly some splashing on to the hot glass will make it shatter!

 

[JohnK]

So it sounds like the glass has a little wiggle room on each side, correct?

Assuming that is right, is it possible that if the lense slides all the to one side there is just enough room for it to drop out? I'm thinking that it might be wandering back and forth in it's holders, maybe because of some vibration, and eventually it works it's way out.

If that is right, then I would think the solution would be to do something so that it can't move all the way in either direction. Maybe something along the lines of sections of thin walled air line tube slit down the middle, then slipped over both edges of the glass. Or if there isn't that much clearance, then maybe a thin bead of silicone along both edges.

Does that make sense?

 

[snowmaker]

Maybe a burr or deformity somewhere in the track the glass slides into?
I mention because tempered glass is very vulnerable at it's edges, but not the faces, which are very strong. The face of tempered glass will take a hammer hit, but just a slight tap on an edge will shatter it.

Have you asked the manufacturer?