Glass or acrylic to shield metal halides?

[abomb]

I'm going to put a shield on my metal halide pendant because I want to put it close to the surface of the tank. the cover will be just a couple of inches from the bulbs. I want to use acrylic because it will pass more light than glass, but I don't know how well it will hold up to the temp. there will be air flowing through it, but I don't know if that is good enough. Can I use acrylic or should I just go out and buy a thin piece of glass?

 

[cmhollis]

I think most halide systems use glass because of the temp, and as an UV shield (pretty sure you only have to worry about UV with DE bulbs).

 

[abomb]

yeah, i guess i should have mentioned that i'm using SE bulbs so UV shouldn't be an issue.

 

[moonpod]

if you're really, really worried about it, get a custom piece of low iron glass.

 

[orlenz]

for SE bulbs you don't need glass or acrylic, it will just trap heat and reduce par.

 

[mcox33]

acrylic will melt in less than a day, been there done that. Plus it stinks. LOL

 

[abomb]

Ok, well I do want to use some type of shield because I have had metal halides that close to the water before and I hate having to clean them and the reflector every week or two. I don't think it will be a heat trap because I will have a fan blowing air directly over the bubls and out of the tank. I think in this way I will be reducing the heat of the bulbs more than if they were just in an open canopy.

Well thanks for the responses, I would like to use low iron glass but I don't think its worth the money for me at this moment in time. I think I'm going to use regular glass so I don't have to worry about anything melting into my tank =)