how big a piece do you need? I have some scrap lying around...

I have seen it at pisces in Calgary by the frozen food

Not sure if this helps or not but ... here goes nevertheless: I once ordered some from an electrical supplier down here in Cowtown. The stuff was easy enough to source, the kicker was that it's something like 5x the cost of white eggcrate. I had sort of come to the conclusion if I ever wanted more, I'd just go with white from where-ever, and then get some Krylon Fusion black paint (well documented on the forums to be safe under the waterline, can get it at Cdn Tire) and paint it black myself.

i wont paint plastic for tanks ever again i had to many issues with it flaking off.

the piece i need is about 12 x 2.5 - 3 inchs.

Yeah thats where I get it, price is crazy though, $20 per 4' x 2' sheet

Ill check tonight, I may have a piece that size