disappearing CYA

Chad-R · Postby **Chad-R** » Wed 13 Jun, 2007 12:39

I wonder if someone can comment on this... when I opened the pool this year, the stabilizer (CYA) level was very low. After vacuuming the pool and backwashing, I then added 10 lbs of CYA (32k gallon pool). Now, just 3 - 4 weeks later, the CYA levels are near zero... according to 2 different tests at the pool store.

After adding the 10lbs of CYA, I've only backwashed one short time and added just a little bit of water to the pool. I don't understand this since CYA supposedly is only lost from water being taken out of the pool... vacuuming to waste or back-washing. Anyone have any ideas where 10lbs of CYA could have gone??? Thx.

Chad R.

Postby **dynamictiger** » Wed 13 Jun, 2007 17:47

What was your test result for the CYA after adding the 10 lbs? Did you add pure CYA or some other chemical that contains CYA?

pk4217 · Postby **pk4217** » Fri 15 Jun, 2007 07:38

what did you use in your pool? all the chemical readings?

if you've found a way to get rid of the CYA, I sure would like to learn about it.

Backglass · Postby **Backglass** » Fri 15 Jun, 2007 08:49

pk4217 wrote:what did you use in your pool? all the chemical readings?

if you've found a way to get rid of the CYA, I sure would like to learn about it.

The easiest way to get rid of CYA is through dilution. Drain some water and re-fill with fresh. There are some chemicals out there that claim to get rid of CYA, but they are very expensive in my opinion ($50 per 10,000 gallons).

Buggsw · Postby **Buggsw** » Fri 15 Jun, 2007 10:41

You don't happen to have a water leveler and high water bills, do you? - indicating a leak in your pool and fresh water being added all the time.

It's hard to imagine CYA disappearing without dilution. Other than that, it takes about a week for CYA to fully dissolve. How are you applying it?
Could you be possibly vacuuming the granules to waste?

rapfeifer · Postby **rapfeifer** » Tue 14 Jul, 2009 18:29

I have this problem too! My levels of stabilizer were steady at 60-80 ppm two weeks ago. Season going well. Two days later, cloudy water, stabilizer at ZERO. We didn't add/drain/treat the water. It's a mystery. I don't want to add more stabilizer because it pretty much has to be there somewhere! I talked to a "pool chemistry specialist" and he said to shock with non-chlorine shock every other day for 4-6 treatments. I've treated 5 times so far, and stabilizer is showing up at 10 ppm...... ideas? Total chlorine is now at 3.5 ppm, free 0.0 . pH is 7.6 alkalinity, hardness all in normal range.

Postby **chem geek** » Tue 14 Jul, 2009 23:28

CYA can get converted to ammonia by bacteria if you let the Free Chlorine (FC) level get to zero, but this is neither reliable nor predictable. If this occurs, it can take a LOT of chlorine to get rid of the ammonia.