Anyone Have/Build A Plywood Tank?

[rastaangel]

Fiberglass is far cheaper then twill weave 2x2 carbon fiber... But I have a 600 yard roll of it that I use for making automotive parts, accent panels, covers, and super light weight sub boxes for sports cars so its not like I cant spare some to do the corners. But I still might use fiberglass just cuz its 1/3 of the price and its all gone be covered with a ton of epoxy anyways.
I would do a closed loop but my grandpa(land lord) wont allow me to use plumbing that that is holding back 100% of the tank volume just in case of failure.
Which makes me wonder... Think all these magnets on powerheads would hold the same of plywood? Think a MP60 would work threw plywood? LOL