Excess chlorine can cause your pool liner to absorb water and wrinkle— we’ve seen liners wrinkle in less than a year because the pool was highly acidic. Too much chlorine can also fade and weaken the liner. We recommend keeping a pool’s pH from 7.4 to 7.8 and checking water chemistry often—even twice a day during periods of heavy use. Here are some other tips to prevent liner damage from chlorine. Be careful not to shock your pool too often. Leave your pool uncovered for 24 hours after adding chemicals. Make sure your pool’s circulation system is working properly so you don’t end up with areas of concentrated chemicals. Don’t use a floating chlorinator. And keep your saltwater system below 3 ppm free chlorine.