Do I have to wait for CYA to stabilize before shocking pool?

[SBenson]

Hi All,
I'm new to the website and am posting my first question. I have an above-ground pool that's 18' x 48". The water just turned green, so I am planning to shock it. When I read the informative thread about shocking a pool, it recommended that I first establish my CYA levels to determine amount of chlorine needed to shock.

So, I added the recommended amount of booster to get my CYA to 70. I ran the pump, waited a day, then retested my CYA. It's still around 30. I just now read that it may take up to a week for the solid CYA booster to take effect. My question is this: do I need to wait a week, re-test my CYA, then begin shocking the pool if the CYA is sufficiently high, or can I just start shocking the pool now, even though my CYA seems too low? Any advice would be appreciated!

Thanks,
Sean

 

[pooldv]

Welcome to TFP!

No, start the SLAM now and assume that it is in there. Although, the SLAM process says to raise CYA to 30. Did you add it in a sock? If it isn't all dissolved then take it out and put it in a bucket for later. Set your chlorine target based on cya of 70 and the Chlorine CYA Chart. Also, adjust your PH to 7.2-7.4 before starting. PH tests are not valid when FC is above 10.

Here is the process, Pool School - SLAM - Shock Level And Maintain

Also, please add your state to your location so we can offer help appropriate for your climate and add your pool info to your signature, more here, Pool School - Getting Started

Here are some of the most important Pool School articles,
Pool School - ABCs of Pool Water Chemistry
Pool School - Recommended Pool Chemicals
Pool School - Recommended Levels
Pool School - PoolMath

 

[domct203]

Hi All,
I'm new to the website and am posting my first question. I have an above-ground pool that's 18' x 48". The water just turned green, so I am planning to shock it. When I read the informative thread about shocking a pool, it recommended that I first establish my CYA levels to determine amount of chlorine needed to shock.

So, I added the recommended amount of booster to get my CYA to 70. I ran the pump, waited a day, then retested my CYA. It's still around 30. I just now read that it may take up to a week for the solid CYA booster to take effect. My question is this: do I need to wait a week, re-test my CYA, then begin shocking the pool if the CYA is sufficiently high, or can I just start shocking the pool now, even though my CYA seems too low? Any advice would be appreciated!

Thanks,
Sean

Why did you raise your CYA to 70? What was it before? Do you have a SWG?

The SLAM procedure states:
"You also need to know your current CYA level, and then look up the corresponding FC shock level. You can use the The Chlorine/CYA Chart at Pool School to find the correct FC shock level for your CYA level."

"SLAMing an outdoor pool is most effective when CYA is around 30 to 40. Below 30 you lose too much chlorine to sunlight. As CYA goes up, SLAMing requires more and more chlorine, which starts to get impractical around 80 or 90. With CYA above 90 we recommend replacing water to get CYA down before you start the SLAM process."

If you have it hanging in a sock take it out now.

Dom

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Also, please add your pool details to your signature. See mine as an example.