How can I quickly reduce Free Chlorine?

[PashkaTLT]

Hello,

I was fighting algae, successfully, but now my FC is 24 ppm and losing about 2 ppm/day. This means I will be able to swim only in 10 days.

Is there a way to reduce FC quickly, besides changing the water?

 

[ajw22]

What is your CYA level?

It is safe to swim up to SLAM FC for your CYA level.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[PashkaTLT]

I had bade test strips and over-added CYA, now it's 90-100.

 

[ajw22]

With CYA 90 you are safe to swim up to FC of 36.

Note that the pH test is invalid when FC is over 10 so don't go adjusting your pH until your FAS/DPD test says your FC is 10 or less.

What do you intend to do about your high CYA level?

Have you done a diluted CYA test to confirm your CYA is around 90-100?

 

[PashkaTLT]

With CYA 90 you are safe to swim up to FC of 36.

Note that the pH test is invalid when FC is over 10 so don't go adjusting your pH until your FAS/DPD test says your FC is 10 or less.

What do you intend to do about your high CYA level?

Have you done a diluted CYA test to confirm your CYA is around 90-100?

I used Taylor K2005 test kit to test CYA. I was out of reagent first and used test strips, which turn out to be bad, that's why I increased CYA even though I already had a good level. Today I received reagent for Taylor K2005 test kit and saw CYA at 90-100.
I intend to do partial drain/refill, but do I really need to do that? What happens if I don't drain/refill and leave my CYA at 90?
I'm not sure what a diluted CYA test is.

 

[ajw22]

I intend to do partial drain/refill, but do I really need to do that? What happens if I don't drain/refill and leave my CYA at 90?

How do you chlorinate your pool?

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

I'm not sure what a diluted CYA test is.

CYA > 90 dilution Test​

For CYA > 90ppm, repeat the test adjusting the procedure as follows:

1. Fill the mixing bottle to the lower mark with pool water.
2. Continue filling the mixing bottle to the upper mark with tap water.
3. Shake briefly to mix.
4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
5. Continue the test normally from adding R-0013, but multiply the final result by two.

If you need to dilute the pool water further then apply these ratios:

Pool water	Tap or distilled water	Multiply result by
1	1	2
1	2	3
1	4	5

Note that when doing a diluted test not only do you multiply the range of the test you multiply the error rate of the test, so results are a ballpark - not an absolute.

See CYA Testing for tips in how to read the test results.

 

[jeffchap]

Don't do anything about the FC. It's safe to swim in now and it'll come down on its own over time.

As for the CYA at 90, there's really nothing wrong with that either as long as you maintain FC at 8 or higher. But drop below 8 and you're asking for algae and if you do get it, it'll take a lot more chlorine to perform a SLAM at that level. Just don't let it get any higher, and it will slowly drop as well.

 

[PashkaTLT]

Thank you, guys.
So, I've decided I will swim & just slowly drain & refill until I get CYA to 50 & FC < 10.