The big fish pond was starting to lose some water so drained it and found to my horror that the liner had perished, this was quite a shock as the liner went under the waterfall, rocks and sleepers. I had no idea how to fix it.
I went to a pond shop and they recommended a product made by Sikka, a marine sealant, so $300 for the liner and another $200 for the sealer.
A very fiddly job as I had to stick the liner onto the rocks ect, I used much more sealer than I thought as I had to make it watertight.
Hell of a job but it worked and I was able to put the fish and plants back and the pond is back to normal.
Moral of the story is do not use a vinyl liner, spend the extra of rubber instead.