shock or not to shock


Active member
Dec 28, 2009
Columbia, SC
First I am very new to the BBB, checked water on Monday:
ph: 7.5
fc: 7.5
ta: 170

did a drain/refill

PH: 7.2
fc: 1
cya: 70

last night about two hours after adding the bleach


this morning before the sun was on the pool

Should I shock? How do I know how much bleach to add to get it to shock level? I saw that somewhere on here but I can't find it now. Water is pretty clear. If I am to shock how long before we can swim? Thanks for all the help, I will get the hang of this.


Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
East Texas
Pool school has the CYA/chlorine chart you need for shock level. And yes, you need to shock. Start at dark. Read the shock section in pool school as well.


LifeTime Supporter
Nov 18, 2009
Sacramento, CA
CYA/chlorine chart will tell you your target level, but use Pool Calculator (link in my signature) to determine actual amounts of chemical needed. Set suggested goal levels at the bottom, size in gallons, and enter then enter "now" and "target" for each parameter and pool calc tells you how much of each chemical to add.


Active member
Dec 28, 2009
Columbia, SC
I just put in 985 oz of bleach to shock level. From what I read I check the FC in an hour and then I check it an hour later. How many times do I do this? I know I have to keep the FC to 28 but I am not sure for how long?


Well-known member
Apr 26, 2009
Northeast Ohio
You should maintain shock level:

1) Until your overnight FC loss is 1 ppm or less;
2) and your CC is .5 ppm or less;
3) or (if you're not using an FAS-DPD test kit), your pool is sparkly clear.

You should test and bring your level back up to shock level hourly if you can, until it's starting to stay fairly high, then you can cut back to 2 or 3 times per day.
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