What should my shock level be?


May 22, 2010
Baltimore, MD
Thanks to this site I've had a trouble free pool all season. It's been clear and sparkly all summer. I'm starting to think about what to do to close it up in when the time comes. I read Pool School and need to know what level of FC I need to shock the pool before buttoning everything up. Per JasonLion's advice I've kept FC between 4 and 8 all season and it has worked perfectly. I'm hoping the winter drain will get the CYA down to a good level for next year.

Can anyone advise me what a good shock level is for my pool? Also, are any of those winterizing chemicals at the pool store necessary? Pool School doesn't mention anything so I'm thinking about not using any this winter.

FC = 5.5
CC = 0
TC = 5.5
PH = 7.5
TA = 130
CH = 60
CYA = 50


TFP Expert
LifeTime Supporter
Apr 4, 2009
With CYA around 50, you shock level is about 20. You can use polyquat 60 at pool closing but it is optional and only needed if you plan on closing the pool early or opening late next season.

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
SouthWest Alabama
I'll just echo what Dman says for confirmation.

I may try the Polyquat this year because it gets pretty warm on some days during the winter around here, but in Md. you won't need it unless like Dman said you plan on closing early or opening late.