testing & treating at a high FC level

[Johnny B]

I goofed by getting my FC to 22 instead of 16, not worried, I'll just have to wait a little longer for it to drop to the proper closing range of FC 12 before I close.
I was going to test pH & was 99% sure it would need acid per my years of experience. No need to test pH with this high FC, it will not be accurate. I assume it is ok for me to add the expected acid anyways? I always take it from pH 7.8 to 7.6 so not a huge change. Or do you want me to wait a day or 2 longer to add the acid? My CSI remains balanced even if my pH gets to 8.2, so it is no problem if you want me to wait because I'm not worried. The real issue/my real question is does this high FC of 22 actually affect the pH in which case if I add acid I will go below pH 7.6 which I do not want to do , or, is a high FC simply a matter of the ph TEST BEING INACCURATE at a high FC rather than the actual pH been affected by the high FC?.

Secondly I assume there's no way to get the FC to drop quicker except draining some & adding water which is kind of stupid I guess? (I want to get the pool closed before the leaves start falling because it will be a lot more work for me). My closing FC range is FC 12, about how many inches of water would you drain to get to FC 14 (just be safe) or don't even bother just be patient?


Thirdly, at this high FC of 22, can I test for CH & CYA & TA and get accurate readings or would you like me to wait until the FC gets to a different lower level before I test these three? If yes what FC?

Thanks

 

[pwrstrk]

You can test your CH, CYA and TA. I would let your FC fall below 10 to do any PH adjustments. The PH test will read a false high at FC levels of 10 or higher.
If you can leave your pool uncovered. That will help with your FC drifting down. It'll take some time with cooler water temps. Replacing water won't help. Just be patient. ?

 

[Johnny B]

Thanks!
I know The PH test will read a false high at FC levels of 10 or higher. But is it just the TEST or is the pH actually different at a high FC, if just the test is off then I'll treat the pH, its gonna take 2 weeks for the FC to get to 10, & I historically treat the pH w acid 1x per 5-7 days. Thanks again

 

[pwrstrk]

From what I've read when you add liquid chlorine (bleach) it raises the PH level in the beginning. After the chlorine starts to get used up the PH level starts to drop. Couple of threads I found.
http://www.troublefreepool.com/threads/4271-Liquid-chlorine-raises-pH
http://www.troublefreepool.com/threads/27716-How-to-test-pH-with-a-high-chlorine-level

 

[Patrick_B]

It's both. The pH does rise initially, but high FC also interferes with the Phenol Red pH test. Always adjust pH before a slam.

If you have a good handle on your acid needs, you can add what you normally do on a regular basis.

Continue slamming, back to normal pH testing when done.

 

[Johnny B]

Thanks guys, so long as the high FC raises the pH, then I know that I am safe to add acid, just wanted to be sure that it didn't lower the pH because then I get CSI problems if I go below pH 7.5

 

[Patrick_B]

No, the initial pH increase from bleach is only temporary. As it is used, the net of that is basically neutral. What I meant was high FC interferes with the pH test. Your pH will tend to rise about the same amount as it usually does through the slam period. If you added acid every 5-7 days, just do the same amount during SLAM. It will be fine.

People tend to focus far too much on CSI. It's really an impractical way to manage your pool, and something you shouldn't worry about unless you are plagued with very high or very low hardness. "CSI problems" are only going to occur during the more extreme situations.