Repairing and patching a pool liner is difficult because you have to first find the leak, hole or puncture. This can be like finding a needle in a haystack. There is no trick or gimmick. There is no product on the market (that works) to find a leak. It is simply swimming around your pool inch by inch with a pair of goggles. If it's not easily detectable or visible you are best served buying a new liner and redecorating your pool.