How Much To Drain to Remedy High CYA

LKSmith

Member
Dec 11, 2020
20
Austin, Texas
Hello again, I had posted back in December, 2020 that my husband had passed in July and I was taking over the pool maintenance. It had high CYA and I was advised to drain and start over. The task seemed a bit daunting and I put off the draining. But thanks to the snow, ice and sub freezing temperatures we got here in Texas last week, it drained itself!!! My power went out in the middle of the night which made my pool & equipment freeze. When things finally began to thaw I found that the pump strainer basket cover had cracked & was draining the pool. I have already replaced the cover. I guess I won't know if there is any other damage until I get the pool filled back up and restarted again. My pool is 16,000 gallons, and I would estimate it is down to about two thirds empty. Is this enough water out to begin filling again and to remedy the high CYA? Or do I need to find a pump and drain it completely? Last test I had done was on January 15, 2021 and the CYA was off the charts high. Thanks for the help! Lisa
 

Newdude

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Jun 16, 2019
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Hey Lisa !!
Last test I had done was on January 15, 2021 and the CYA was off the charts high
Did you do a dilution test or just quit at over 100? Depending on how high (per only the TF-100), a 1/3 drain may have been enough along with the natural degrading over several months. (About 5 per month). Or it was 450 and you’ll still be 300 after filling. If you can lower a bucket or something into the pool you can test it to get us a *now* # and we can go from there. Take the sample inside to warm up to room temp. The cold messes up the CYA test.
 
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ajw22

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Jul 21, 2013
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In this thread you said your CH was 1250 ppm and CYA was 160 ppm....


If you lost 1/3 of your water and refill you should have CH around 800 ppm and CYA around 100 ppm. That is still too high.

You need to drain about 1/2 of what you have or 2/3 of the water you started with. With 1/3 of the original water you should end up after a refill of CH around 400 and CYA around 50.

Your first thread had tips on how to drain.

 

LKSmith

Member
Dec 11, 2020
20
Austin, Texas
I pulled the plugs on the pump which is continuing the drain. So I should be pretty empty in another day or two. Will report back. Thank ya'll so much for your help & support!
 

mknauss

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Be careful draining your pool if you are in an area that the soil is saturated. The pool shell can pop out of the ground.
 

LKSmith

Member
Dec 11, 2020
20
Austin, Texas
16,000 gallon pool is down to about 6,700 gallons. CYA level in the CYA View Tube is about half way from bottom of tube up to the 100 reading. Drain more water or is this enough water drained?
 

ajw22

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You want to get it down to between 5,000 - 6,000 gallons.

There are lines and numbers on your CYA tube for you to properly read it.
 

LKSmith

Member
Dec 11, 2020
20
Austin, Texas
It is down to 6700 gallons. Is that not close enough?

The amount of pool water/R-0013 I put in the CYA Viewing Tube until I can no longer see the dot on the bottom does not even reach the lowest line on the tube (100 reading). It is half way from the bottom of the tube to the 100.
 

ajw22

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That says your CYA is over 100. Earlier you said your CYA was 160. Do the dilution test as described below.

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.
 
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ajw22

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Drain another 1,000 gallons to ensure you don’t need to do it again anytime soon.
 

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ajw22

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What is your pool water temperature? Let the CYA test warm up above 70 before mixing reagents.

If your pool has stopped draining naturally then close things up and start filling it. We will see where you end up.
 
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LKSmith

Member
Dec 11, 2020
20
Austin, Texas
I did the dilution test using 1/3 pool water 2/3 tap water. It registered at about 120 CYA, multiplied by three = 360. ???

Should I go rent a pump to remove more water? I hate to fill, then have to empty again.
 

kellyfair

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Hello! Did you do the dilution test as described? If so, you would multiply by 2, not 3.

I’m a bit confused by your description of testing 1/3 pool water to 2/3 tap water.
 

Newdude

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I’m a bit confused by your description of testing 1/3 pool water to 2/3 tap water
If half and half still reads over 100 you have to keep going in equal parts until you get a reading under 100 (or 100) and multiply by the parts used. 1/2 and 1/2 is X2. 1/3s is X3. 1/4s X4 and so on.
 
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LKSmith

Member
Dec 11, 2020
20
Austin, Texas
Yes, I did it as described and multiplied it by two the first time, but still got an unregisterable result. That is why I did the dilution test with 1/3 pool water to 2/3 tap water. Just a little more dilution, and then multiplied by three, to try to get a result that would register on the CYA Level Viewing Tube. Still registered over 100.
 

Newdude

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I did the dilution test using 1/3 pool water 2/3 tap water. It registered at about 120 CYA
You cannot read over 100 even though it seems you can. You have proven however to be above 300. Minimum drain to get to a CYA of 30 would be to drain 90% of your pool volume. If it’s even higher than that it would need more.
 

kellyfair

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You cannot read over 100 even though it seems you can. You have proven however to be above 300. Minimum drain to get to a CYA of 30 would be to drain 90% of your pool volume. If it’s even higher than that it would need more.

LOL, I had to set it up like this:

aa+ bb=abab
Divide by 2 = ab
ab + bb = abbb

It wasn’t computing that it would be 1/3, not 1/4!
 
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