Pre-formed pond liners

[SaltyJim]

So, how strong are these things? I was given a 30(ish) gallon in ground pond liner (round, four "shelves" molded in the bottom), and I was thinking of making it a fuge or frag tank. I did a small test with the liner on grass, filled and left for a few days. No problem with strength for that test, but that also wasn't in the house or with $$ in livestock. Am I risking too much trying to use this above ground and with salt water?

[Entropy]

I have seen a similar liner used at Home Depot and it survived at least six months. They changed their outside area, so I don't know if it finally failed or they just emptied it. Anyway it was just supported on the bottom by the ground and along the rim with stacked blocks. I think in a perfect world they are supposed to be supported by backfill all the way around though.

[SaltyJim]

yes, they are definitely supposed to be supported by backfill...

since they are round, physics tells me that the structure should withhold the pressure of the water. But, after a few months, I have concerns about the rigidity of the plastic. I think frag tank is out of the question though. The UV would make the ABS brittle I think.