WInter CL levels and liner damage??

[ship of fools]

OK .... first year here and i am very happy

but now that i have an understanding of pool chemistry i have a question...... when i hired someone to close my pool and when i did it myself the process involved putting in 5 gallons of liquid chlorine ... which i now know to have been 12%.

my pool goes up 1 ppm with 44 oz of 6% ..... so that would mean roughly 6 ppm per gallon of 12% so when i close the pool i have roughly 30 ppm plus the 5 ppm or so i normally run with

if there is a concern for high chlorine levels causing damage why doesn't the water in the winter cause issues??

 

[JasonLion]

It is not normal, or recommended, to use that much chlorine when closing in the winter. We only recommend going up to shock level. No matter how much chlorine you use, it will invariably be gone in the spring, so using more doesn't really help. The main thing is just to make sure there isn't any algae already growing when the cover is put on.

 

[BadOleRoss]

Last year was my first year using the BBB method. When I closed my pool, I waited for the pool water temps to be in the 50-55 degree range before I closed it. I adjusted all of my levels (PH, TA) added polyquat and brought my FC level up to shock level and covered the pool. I opened the pool when the water temps were again in the 50-55 degree range. Other then the small debris that had made it's way through or under the cover my water was crystal clear. I still had .5PPM of FC in the water which really surprised me. IMO, a key component in closing is to wait until the water temp drops so algae can't get going before winter sets in.