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430gallon plywood tank build


Jun 21, 2007
I know i have not posted here in a few, well i have been day dreaming on this project, i was racking my brain about what to do to get my 75gallon empty so i could use it for a octo tank, well here is what i came up with, i dont want to double post this stuff so here is a link, let me here what you think so far!
Inwall 430gl Plywood Tank Build
I am glad you are going to clean that monster and not me! Have you got a game plan figured out if it leaks? That's a LOT of water and pretty hard to leak test. Definitely would make me nerveous (of course our next one goes over a stairwell :wink: but it will be way smaller!)

Please update this thread when you post more pics so it gets bumped for another look.
We built a few plywood tanks at the zoo (freshwater) and they held up for a year or two, but they ended up being more expensive than acrylic in the long run. Interesting project, keep those pics coming.
i posted a pic of it fully fiberglassed and with the second coat of resin! i think i got more on me then the tank but the hard part is now done, just got to add some more coats of resin and sand it then its glass time! thanks for the good words!
You might detail some of the problems (I always wondered about this kind of tank) and give suggestions for avoidance and/or detection.
Well, the biggest issue we ran into was with the warping of the plywood over time, leading to joint failure. In the end, a steel frame was used to keep the ply in place, but by the time we were done with all of the welding, etc, it would have been cheaper to just have used sheet acrylic or glass.
The tanks held up for a few years, now they use them dry as housing for juvenile tortoises.

I've seen some pretty nice European wood tanks, so I know it can be done, I just have a feeling that our extreme temps here in AZ may have led to the premature degredation of the plywood.
Did you seal the wood inside & out? I've been thinking of making a monster ply tank (10'x4'x4') for my cichlids to free up some smaller tanks

Was planning on reinforcing with angle iron, making a box frame around the outside - welding I have no problem with

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