loss of stabilizer

meber

Member
Aug 11, 2008
22
central kansas
My cya was 20 and I was using more bleach per day than I wanted. I added 4 lbs of stabilizer to bring my cya up to 40 and my usuage dropped in about half. My demand went back up about 3 weeks later, rechecked my cya and it was down to 10. I had to backwash 2 times in the last 2 weeks and had about 3 inches of rain. Yesterday i added another 4 lbs of stabilizer and am using 7PPM of bleach per day. What am I doing wrong?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Do you have an auto fill system, or have you been adding water to the pool frequently? The most common way for CYA to go down is a water leak that results in a lot of water replacement.
 

duraleigh

Admin
Mod Squad
TFP Expert
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In The Industry
Apr 1, 2007
31,691
Sebring, Florida
I can't answer what happened to your CYA but if it's gone I would replenish it to 50ppm in your climate.

I would also suggest you do a full set of tests to include CC's. I'm purely speculating but you maight have a little algae in your pool.

One note, CYA takes up to a week to register on the test after you put it in. I can't tell from your post whether or not you have given it enough time.
 

Butterfly

TFP Expert
LifeTime Supporter
May 30, 2007
10,045
South Carolina
How are you adding your CYA? Directly to the skimmer or using the sock method hanging in front of a return?

If you added CYA via the skimmer and then backwashed before a week's time, this could account for loss of CYA.

Also, losing 7ppm FC daily, I also suspect some organics.

I'd do an overnight free chlorine loss test - directions in Pool School.
 

bk406

Well-known member
Dec 3, 2009
2,690
Central Massachusetts
My pool eats CYA. I have no leak, dont add much water (maybe an inch a week right now in 90+ weather), dont backwash much (one a month maybe) and not a lot of rain this summer, either. I had 60 ppm at the beginning of May. Measured it a couple days ago, it's maybe 30 ppm. I have no ammonia. I have no idea why I cant keep CYA in my pool, none. It just add more when I need to. I gave up trying to figure out why. In the spring when I open, my CYA is zero. No ammonia either. :?: :?:
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
meber and bk406,

Have either of you used enzyme products? Do you have unusually high chlorine demand? Is your pH on the high side (7.8 or higher)? A loss of 30 ppm CYA in 75 days is 0.4 ppm CYA per day. If it were chlorine oxidizing the CYA, it would be around 1 ppm FC per day extra chlorine demand. The more normal CYA loss (with no dilution) is usually less than 2 ppm per month instead of the 12 ppm bk406 is seeing. In hot (104ºF) spas with 4 ppm FC and 30 ppm CYA, we've seen a drop of 5 ppm CYA per month consistently measured from multiple people.

Richard
 

bk406

Well-known member
Dec 3, 2009
2,690
Central Massachusetts
I use no enzyme products. Only thing i add other than chlorine is some metal control from HTH, but not much of that. I keep my TA at 80, CH is 40, pH stays around 7.4. I have not added one drop of acid or one flake of borax since i opned. pH is rock steady. I keep my FC around 6 ppm. My pool seems to use around 2-3 pm per day. Nothing extraordinary.
 

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