Looking to start a frag tank. Is it "egg crate" that is used to build the shelving ? If so, where do you buy it. If not, what the heck is it called ? And where do you get it ?
The 'egg crate' you refer to is actually light diffuser. It is found in one of two departments in HD. They carry them in either/or the ceramic tile department where they have the ceiling tiles, or the lighting department where they have the large fluorescent fixtures.
You can use 1" pvc pipe with fittings to raise it to the level you want. Use a 1/8" drill bit, drill the pvc then loop a cable tie through the pvc and the egg crate.