Backyard Aquaponics
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I have a small apartment system with grow bed being a box made out of 1 by 10 lumber and plywood on the bottom. The box is lined with durascrim, filled with hydroton, and a few bulkheads go through the liner and plywood. This was holding quite well for almost 2 years (that bell siphon was like a plumber's clock!), but started leaking recently, a slow drip at first which I tried to redirect, but increasing steadily. Not a good thing in an apartment

So I took it apart, sealed bulkheads with aquarium silicone and rigged it back with just system water (no media). Only to see it leaking again through the liner directly! It seems layers are delaminating in the liner and water seeps through. I even saw little bubbles forming on the perfectly flat area. There are no bubbles in the rest of the system, so it doesn't seem like out-gassing from the water itself.

After disassembling the box, plywood under that area was wet. And that was 50 cm from the nearest bulkhead with dry space between, so definitely not a transfer.

I also saw drips forming on exposed part of the liner (didn't fit a section of plywood for the test), but couldn't tell for sure if that wasn't simply water leaking from the nearest bulkhead collecting at the lowest point.

Is that an expected failure mode for durascrim after 2 years or did I screw up during the build somehow?

One thing I could think of is water-based polyurethane finish on the plywood being in direct contact with the liner and having a chemical reaction with it. Maybe some water got there and it was sitting wet for 2 years dissolving the liner...

You can see discoloration on both plywood and the liner below.






And system pics just because

Welcome to the forum UFO

Welcome to BYAP. Bummer about the materials leaking. I've been there more than once. I had to bite the bullet and bail out on my fiberglass lining job on three out of four beds. I went with 7'x10' (2.1m x 3m) pond liner and so far no more leaks. Like you, I tried to fix leaks, but the hassle is too great if it doesn't hold water or holds for a while and then gives out. Great looking system. Good luck.

I have always wondered how well those scrim fabrics things held up. Is this a commercial grade material or just something off the shelf from a local box store advertised as ' waterproof'? I know they are used as pond liners and in holding ponds for various wastewater scenarios, so I am a little surprised that the life span would be so short. Guess i'll google durascrim...

They have this warranty.
5 year limited UV warranty. (Does not cover normal wear and tear or improper installation.)
You should check if they will cover this under the warranty.
I am also using this product so I would be interested to see what they say.

scotty435, boss, thanks

Poppa, yeah, this is a commercial type of liner, this stuff: http://www.americover.com/images_templ/ ... eeting.pdf

markb, Hm, this is not UV related for sure, leaking parts didn't see any light at all... I bought it from a guy who built his own system and had leftovers, so I can't even tell how old it was originally and how it was stored. Given all that I seriously doubt any warranty would apply .

I'm more interested in figuring out what to use as a replacement now. Either leaving it as is and painting with liquid EPDM or replacing with the new hot thing: Ultra Scrim FGC. Maybe I'll leave a layer of old liner between new one and plywood this time...

Anybody has experience with Ultra Scrim?

For your size system I would check out fiberglassing the inside....

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