Repairing a punctured liner
FIND THE HOLE! The hardest part is tracking down where the puncture is! The hole/rip can be tiny and nearly invisible when the liner is dry and the weight of the water isn’t forcing the hole open. It is usually on the waterline, so let the water drop as low as it can and mark that level. Then drain/pump out more of the water to about 2 inches below your marker. You now need to check round the circumference of the pond 2 inches above the water line. Use a nylon scourer to gently clean off any algae and dirt and press each section with your fingers. The soil behind the part that is leaking is likely to be very wet/soft so you may be able to feel a difference as you go round. It can also help to shine a very bright torch on each bit as you go round to help show up any difference in liner texture.
Once you’ve found the hole, you need to clean around the area (just use warm water and the scourer, no soap or chemicals!) and let it dry. There are different ways to patch it, depending on the size of the damaged area:
Ideal for larger punctures- run a bead of aquatic safe silicone about 1cm thick round the hole. Press a patch gently over the silicone. Don’t press the silicone flat, it should still be about 5mm deep! Some silicone needs 24-48 hours to cure before refilling the pond.
Ideal for smaller punctures, up to 1cm. Simply cut off a strip of the tape and position it centrally over the hole. Press gently into place. Peel off the paper backing and stick a patch of liner onto the sticky surface. Press it firmly into place, all around the edges of the patch. Pond can be refilled instantly.
One last thought—there’s no shame in defeat! Even professional pond maintenance experts can’t track down every leak and sometimes it’s easier on your blood pressure to just replace the liner!