I used fiberglass resin first then epoxy paint. You could use epoxy by itself but epoxy does not have any structural strength it is more of a water sealant so you better make sure your setup is solid with extra bracing. If you use resin and fiber in the joints then just resin on walls it will make the pond stronger and makes it last longer. Just make sure the resin is cured then lightly sand before the epoxy is added.
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