Pamsel, We had a new vinyl liner installed last year. I used bleach for 1/2 the season, had to use a few jugs of acid to straighten out the pool store recommended mess my water was in, closed the pool with bleach and opened this spring with bleach. Liner still looks brand new.

I add bleach after sundown, and pour it directly into the skimmer. This way it's diluted when returned to the pool, and get's evenly distributed.

When I added the acid, I did it slowly, pouring a small stream in front of the return stream, to make sure it was dilluted and dispersed before it ever had a chance to contact the liner.

Good luck. The light is at the end of the tunnel, and it's so much easier/cheaper staying ahead of a pool that playing catch up.