do not use the egg crate...it is designed to difuse the light in any light fixture....I made my own screen tops with material from Lowes in the screen section in hardware, they have everything you need but the screen....I used a 1/4"x1/4" square mesh I got from another reefer who ordered it in bulk and sold off what you needed to make your screens tops....same thing as brs, but look around I am sure you can find it cheaper than what they sell it for, think I paid like 3.00 for screen and .44 for shipping.....I will try and find his email and see if he still has some for sale