Question on de metal halide glass

[kware]

I have an odyssea 48" metal halide t5 combo light
Its a cheaper light but it seems to work ok. My question is one of the glass panels covering one of the 250 watt de halides is broken. It got water splashed on it and it shattered. I found a guy on ebay who says he has the replacement glass but its not a uv filter. Do the de halide bulbs require uv filter glass. That being said its been broken for a a few months now and the corals or fish dont seem to mind.
Any thoughts on this? Can i use glass thats not a uv filter?

 

[Big E]

You need the UV filter........without it you will burn the corals. Your current light with the crack probably isn't split enough to let anything get by.

If that crack does separate you will see a line of burn across any coral underneath it.

Spend the money and get a UV glass replacement before it becomes a problem.

 

[kware]

The funny part is about 70 percent of the glass is missing. Theres just a small shard left about the size of a half dollar. All the inhabitants seem fine. Maybe because its a relatively deep tank (24”)? My problem is i cant find a replacement for it otherwise i would. Its a pretty new light fixture and im avoiding buying another one.

 

[dadnjesse]

Why can't you go to a glass place and have one cut to fit

 

[Michael Hoaster]

I don't think you need UV filter glass. What filters UV in Nature?

 

[alton]

I asked for permission to use this in 2006 from Coral Magazine, hopefully that permission is still good? I actually have every copy of Coral Magazine except the one that was never released

 

[Michael Hoaster]

Pretty convincing article. I have kept 400 watt metal halide lights for years with no UV glass, and no problems.

 

[Big E]

SE bulbs are UV safe due to the glass they are made of. I had one crack once and it seared a line across all my acros that were below it.

I never used DE bulbs but the reflectors glass was designed to block lower UV rays that they give off. I don't know the exact science but the glass(doesn't block) or design of DE bulbs creates UV that needs to be blocked.

There aren't levels of UV in nature as low as what a DE bulb gives off. These very low levels aren't natural. I think it's 350nm and below where it's a problem.

Talk to the makers of DE bulbs and I'm sure they can give you more technical advice.

 

[kware]

I believe the glass needs to be tempered and you cant cut tempered glass. That's why class stored don't have it but that's just my theory I haven't asked any glass stores that.

 

[LesMartin]

From memory: It's not a special type of glass for UV blocking, nor does it have any type of UV blocking coating. It's just that glass blocks UV. All you need is tempered glass to cope with the heat. DE bulbs are quartz glass which doesn't block UV, hence the need for the additional glass shield ( it's also the reason why you shouldn't handle DE bulbs with your bare hands- the quartz will absorb the oils from your skin and the oils will burn in shortening the life of the bulb). Single ended bulbs have an additional glass outer which is why you don't need the glass shield.

 

[josbur63]

Why not just get a glass cover for the tank.They have replacement covers on Amazon for $40.That should be tempered glass and it will protect your bulbs from water while also providing uv protection.

 

[zues2006]

This is good info. I have a double ended bulb pendant and the glass broke on me. I know people mention a glass shop for replacement, but are there any specific ?
DO I just call around for some local glass companies ? Will they cut my 4"x 6" piece for a reasonable cost ? Anyone have a ballpark price that may have paid to replace one ?

Is all I ask for is: tempered glass ? what about thickness, bevels, etc ? Does any of that matter ?

 

[kware]

I talked to the people at the glass store today and they can cut me high temp glass made for wood stoves. Not tempered tho??
Also much cheaper. I wonder if that would work?

 

[mcgyvr]

From memory: It's not a special type of glass for UV blocking, nor does it have any type of UV blocking coating. It's just that glass blocks UV.

Regular soda/float glass blocks UVB (what causes sunburn) but not UVA..

UVA blocking glass is typically available at any glass shop.. Just ask for it..

 

[kware]

I will call a few glass shops tomorrow and see what they say. I will keep you guys posted.