My liner was 9 years old when I had to replace it, and the original rips that caused the need for replacement were well above the waterline, not below....

The calcium in our fill water is less than 20 ppm and I think I might have used cal-hypo for chlorination 4 times in that 9 years, in a pinch when I was out of bleach. So you can add that one to the count...

Janet