Water readings


Well-known member
May 15, 2010
Dayton, Ohio
About 10 days after filling (and after reading and re-reading EVERYTHING from Pool School) this is what I have:

FC 5
pH 7.0
TA 200 (down from 300)
CYA 55/60

I have driven my pH down with muriatic acid in order to get the pH down. Am aerating to get it back up and then will use acid again to bring pH down. Will keep on going unti the TA is appropriate. My CYA is a little higher than it should be. Is that ok or is there something I should do about it?

Any comments would be appreciated.


LifeTime Supporter
Nov 18, 2009
Sacramento, CA
Hi :wave:

Your FC is at the minimum for your CYA. You should target 9 when you add chlorine and don't let it drop below 5.

Your pH is low, but with a TA of 200 I am sure it will quickly get up past 7.2

You might want to test the TA of your fill water. Is that where all the TA came from or did you add Baking Soda?

The high CYA just means you will have to maintain higher FC and if you have to shock that will also require higher FC.

The only way to bring CYA down is with partial drain and refill. If the pool gets full sun it is probably fine. Splash out and refills will bring it down slowly anyway.


Well-known member
May 15, 2010
Dayton, Ohio
Wow! Thanks for the quick reply. The TA of my fill water was that high (300). The only things that have gone into the pool are 10% liquid chlorine, CYA, and muriatic acid. I would partially drain it to bring the CYA down a bit, but I am just beginning to to get the TA under control. Is it in my best interest to have the CYA down or keep working on the TA situation?


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
It sounds to me like you have a good understanding of what you're doing and that's what BBB is about. I suggest you leave your CYA alone. In your area 40-50 is probably perfect but you will hardly notice the difference, if any. You may even consume a little less chlorine by having it at 50-60. It'll probably come down into the 40-50 range over the summer on it's own, as well.

As svenpup said, keep your chlorine up. 4-7ppm would probably work but his suggestion of 5-9ppm might be a little safer.

Anyway, keep working on your TA for now. The CYA may be a little lower on it's own after some time has passed.

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