Quote Originally Posted by aylad View Post
Why do you shock it so often? Unless you're having a problem, see algae starting, or are losing chlorine overnight, there's really no reason to shock it on a regular basis. However, with your CYA at 25, you need to keep the chlorine between 3 and 6 ppm at all times. Be careful about shocking with the cal-hypo, though--your calcium level is climbing, and it won't be too much longer before you start having cloudy water issues due to the calcium....

With the best guess chart, the left-most column shows your CYA level, the next one shows the minimum and maximum chlorine levels that you need to keep in your pool for that CYA level, and the next column shows how high you need to take your chlorine to achieve "shock" level. The right-most column is for those who have mustard or black algae, or some other water problem that does not respond to normal shock levels.


Janet
Thanks again, Janet -

So to confirm that I'm understanding the Best Guess chart, assuming that my FC is 1.5 and if I round my CYA up to 30, would I add approximately 5 gallons of 6% bleach to achieve an acceptable "shock" of 15 ppm?

For my current practice, my local store recommended shocking 1x/week with the Calcium Hypochlorite. I've extended it to once every 10 days or so but now realize that even this may be overkill. The kids are in it literally every day so I've been trying to avoid getting behind the 8-ball with the chemicals.

Another question: the pool store told me to keep the FC between 1-3ppm. They didn't seem concerned about the CYA so long as my FC level stayed within reasonable limits. Should I be keeping it higher?

Jim