CYA Too High?

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C

cdogstu99

0
Oct 7, 2014
111
Braintree, MA
I've gone through pool school and followed the Pool School method for years.

I have the following readings on a 8-10,000 gallon above ground pool

FC 12.4
PH 7.2
TA 40
CH 40
CYA 100

The water is crystal blue and I just opened it about a few weeks ago and have been shocking with liquid chlorine.

I also added a four pound bag of stabilizer the other day, since I use well water that usually throws the chemicals out of whack.

I suspect maybe that's why the CYA is so high?

My question--is that a safe level for swimming? And if not, is there something I should do to adjust? Thanks!
 
It's safe, but difficult to manage. If you arrived at your result without using the diluted sample method, follow the instructions below and report back:

If your CYA level is 90 or higher, repeat the test adjusting the procedure as follows:
  • Fill the mixing bottle to the lower mark with pool water.
  • Continue filling the mixing bottle to the upper mark with tap water.
  • Shake briefly to mix.
  • Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
  • Continue the test normally from step 2, but multiply the final result by two.
 
According to pool math, you just added 48 PPM of cya to your pool, assuming your pool is indeed 10,000 gallons, as far as I no, high cya levels are not unsafe, it just makes your chlorine less usable, you would need a whole lot of chlorine to compensate for your high cya levels.
 
Rancho Cost-a-Lotta said:
It's safe, but difficult to manage. If you arrived at your result without using the diluted sample method, follow the instructions below and report back:

If your CYA level is 90 or higher, repeat the test adjusting the procedure as follows:
  • Fill the mixing bottle to the lower mark with pool water.
  • Continue filling the mixing bottle to the upper mark with tap water.
  • Shake briefly to mix.
  • Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
  • Continue the test normally from step 2, but multiply the final result by two.
Click to expand...
Ok thanks I did this. The water did not make the little dot cloudy at all......
 
Just a few minutes is enough. And I typically try to add them at opposite ends of the pool.
 
cdogstu99 said:
Ok thanks I did this. The water did not make the little dot cloudy at all......
Click to expand...
You saw the dot at 20 on the diluted test, half pool water and half tap water? That indicates your CYA is less than 40, which is contradictory to the 100ppm that you gave at the start.

I'd do the normal CYA test again and see what you get. If it's still over 100, re-do the diluted test.
 
Also, you can use a 10ml sample for the FC test, one scoop of powder, and each drop is 0.5ppm. That'll save you reagents.
 
cdogstu99 said:
Ok thanks I did this. The water did not make the little dot cloudy at all......
Click to expand...
I think you may have missed a step. You should see a result of at least 40 ppm. Were making a 50/50 sample of pool water and tap water.
  • Fill the bottle to bottom of label with pool water
  • Now fill to the top of the label with tap water...shake (the bottle no you)
  • Drain off half to bottom label (50/50 mix of pool/tap water)
  • Now fill with reagent R-0013 to top of label
  • Perform test in CYA cylinder
  • Double the result
Wanna try again?

Do you have a SWG?

Would you be able to drain and refill 50% of your water?
 
Rancho Cost-a-Lotta said:
I think you may have missed a step. You should see a result of at least 40 ppm. Were making a 50/50 sample of pool water and tap water.
  • Fill the bottle to bottom of label with pool water
  • Now fill to the top of the label with tap water...shake (the bottle no you)
  • Drain off half to bottom label (50/50 mix of pool/tap water)
  • Now fill with reagent R-0013 to top of label
  • Perform test in CYA cylinder
  • Double the result
Wanna try again?

Do you have a SWG?

Would you be able to drain and refill 50% of your water?
Click to expand...
Sorry I missed adding the reagent part....this time around its at 80....so i guess 160 if i double it?
 

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cdogstu99 said:
Sorry I missed adding the reagent part....this time around its at 80....so i guess 160 if i double it?
Click to expand...
Yep. You'll probably want to replace about 75% of the water to get the CYA down to about 40 or so.

CYA of 160 requires you to keep the FC up above 12 at a bare minimum, which will be very prohibitive to do, and make your pH testing unreliable. You're flirting with an algae bloom.
 
Prior to adding the stabilizer, your CYA would have been over 100. Any idea how it got that high. Did you use tablets in the past? Granular shock?

If your confident you performed the CYA test correctly, you'll need to drain about 60% of your water to get CYA down to the upper range for a non-SWG pool. FC/CYA Levels You can drain off as much as 75% as recommended by @IceShadow.
 
Rancho Cost-a-Lotta said:
Prior to adding the stabilizer, your CYA would have been over 100. Any idea how it got that high. Did you use tablets in the past? Granular shock?

If your confident you performed the CYA test correctly, you'll need to drain about 60% of your water to get CYA down to the upper range for a non-SWG pool. FC/CYA Levels You can drain off as much as 75% as recommended by @IceShadow.
Click to expand...
I have no idea, the only thing I did was add a few gallons of shock. Had an issue where filter was broken and spitting sand back into the pool but that's about it. I do use well water, and each season I use the conditioner because of it, I guess I just overdid it this time....
 
Yes. Some accuracy is lost with the diluted test. Don't be surprised if you over/undershoot the target.

After you exchange the water, test CYA and adjust as needed. Maintain FC levels recommended in the FC/CYA Levels.

Sorry this happened to you :(
 
So i did empty half of the water and replaced it with water from my well. I added a gallon of shock too and the water went from crystal blue to a greenish color. Note this usually happens when I fill up with a lot of water from the well. I've added liquid conditioner before and it always seems to correct after adding the well water.

Of course I ran out of the 0013 chemical to test for CYA (and Amazon is delayed).... I'm not sure If i should just add in more of the liquid conditioner i have (has seemed to work every year for the last five years)...or is there something else to consider while I anxiously await (3 days) the shipment of the 0013.
 

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