which filters light out more... acrylic or glass?

[gotseamonkey]

I'm thinking about making a acrylic lid for my tank because I want to keep a purple fire fish and heard they jump out all the time. I'm using halides with low to moderate light corals so I'm not too concerned with the extra watts being filtered out. Would acrylic be ok? or is glass better? Thanks.

[Chasman]

The halides will warp the acrylic unless you use something pretty thick. Nothing the box stores sell will do. Glass is heavy but better. Some guys use egg-crate to mak a jumper shield. Never tried it but I see it recommended all the time. That (egg crate) you can get at Home Depot or Lowes.

[Original Fin]

I'm not really sure about which would be better, but you may run into issues with gas exchange. CO2 buildup is what I'd be. Concerned about. This would have a tendency to drive PH down.

Have you considered netting of some sort? Somebody sells a kit for this where you use vinyl window screen material, and cut a frame to size. Maybe Bulk Reef Supply?

[FoMoCo Master Tech]

I plan on using egg crate for jumpers. It's cheap and easy to find.
I think closing the top with glass or acrylic may cause heat issues ( no where for the evaporated water vapors to go). Gas exchange would be an issue for sure.