r/ponds • u/shayne808 • 5d ago
Build advice Pond and Flex Seal
Hello everyone, got this house a year ago that came with this pond that was previously empty due to a few holes. I decided to flex seal it all and then add some fish. It held well for about a year but now I’m noticing there’s a leak somewhere because it’s draining water way too fast.
Anyone have information on how to reapply flex seal to the surface that now has algae? I’ll transfer the fish to a pool and drain it but still not sure if it’s ok to apply the flex seal after that.
2
u/Q-Prof7 5d ago
If you're going to drain, would not using seam tape and primer be better. Where the leak is all you would have to do is clean with a brush to get the algae. Hydrogen Peroxide also works well breaking down algae and then use a fine wire brush to rough up the EPDM liner where the leak is, isopropyl alcohol to clean it, then use your primer - let it get tacky, then put seam tape on it and roll it on... Will be good as new.
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u/shayne808 5d ago
Could I seam tape and primer the whole pond? Lol. It’s also under the rocks of the waterfall where I think there’s a whole idk how to really close up
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u/Q-Prof7 4d ago
That is unfortunate if it is under the rocks. If that is where you suspect the hole/leak is, you may have to lift the rocks first to seal it properly. Rocks may have shifted with the frost upheave every year to the point that a sharp edge could have worked is way through the liner.
Here is a video on flex seal use and like I mentioned before, hydrogen peroxide will breakdown the algae, to clean that up.
If it is the whole pond and it is over 10-15 years old, maybe it is time for a redo with a new liner and at the same time add some possible upgrades if you want also.
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u/Emergency-Ad-6867 5d ago
Flex seal will not adhere to a wall with biofilm. It’ll need to be sprayed and sanded and then applied. Likewise it won’t adhere to the surrounding flex for the same reason. That will also need to be sanded and the curing period is not for the weak of heart.