# Thread: What is shock level with CYA of 60

1. ## What is shock level with CYA of 60

Originally Posted by JasonLion
It is time to shock the pool. With a CYA level of 60 your FC shock level is 18. The basic idea is to test the FC level, add enough chlorine to bring FC back up to 18, and repeat that process frequently (as often as once an hour, as infrequently as twice a day) until the FC level holds overnight and the CC level is zero. There are instructions at Pool School.
Just clarifying for myself, for a CYA level of 60 wouldn't they need to bring the FC level up to 24 to shock. That's what I would think based on the CYA/Chlorine relationship chart. I just want to make sure that I'm understanding the chart correctly.

2. ## Re: What is shock level with CYA of 60

There are two different CYA/Chlorine charts. I tend to use the one in my Pool Calculator, other people use the one in Pool School. Pool Calculator says 18, Pool School says 24. As it happens, either level will work. Raising FC to 24 will require more chlorine, but will work more quickly.

3. ## Re: What is shock level with CYA of 60

OK, thanks. I was actually just playing with the calculator putting in different numbers and seeing the results. The more I use it, the more stuff I find that it does. I actually had just clicked on the heading "Suggested FC Levels" and read the notes. Until tonight, I didn't know there was info under each heading. Cool app.

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