Egg crate as tank screen may reduce a substantial amount of light going into your tank, if you have photosynthetic animals, that may be a concern
BRS sells rolls of this fine mesh 1/2" and 1/4" plastic screening that you can stretch over screen frames. It doesn't seem to deflect detectable amount of light going through it. Just as soon as I get rid of all my wires coming out from the top of my tank, I'm putting one in, too.FYI
