Besides harsh chemicals, one of the worst enemies of vinyl liners is ultra-violet light from the sun.

UV rays hit more on the northern side of the pool, and that can cause bleaching where the sunshine hits it above the waterline, techs say. To prevent this, place the water level up higher than you normally would on other types of pools.

UV will do the most damage on pools where the vinyl liner was incorrectly installed. UV can really affect the liner if it was overstretched when it was put in. If the vinyl is overstretched, it thins out just above the waterline and that’s where the UV is going to attack it. You end up with premature wear due to faulty installation.

One solution is to convince the customer to add a cover to the pool if it doesn’t already have one. If the customer opts for a solar cover, though, don’t pull it completely over the edges of the wall. This will physically heat the vinyl it comes in contact with, causing it to degrade. With any floating-style cover, leave an inch around the pool between the end of the cover and the wall.