just about any hardware store in the lighting department
+1 I got mine at Lowes.
just about any hardware store in the lighting department
YEa Iused it for my 180 african reef tank and my salt water tank. Just protects the glass so much better. Rock falls it wont blow up your tank also those teny tiny little pointy edges and imperfections rocks have that can create cracks or breaks in glass are safely dispursed through a larger area with the egg crate... Stuff is amazing, super cheap too. If you going to put ANY rocks in your tank I recomend using it.