CYA test results and adjustment

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S

Susanmi

0
Jul 27, 2017
14
Saginaw MI
Hi all, I've just used my new Taylor K2006 kit for the first time. Had trouble with the CYA test (black dot never disappeared.). I think this is because my CYA was too low to read. I took a sample to my pool store, and they got a CYA reading of 31. All of the other results were basically the same as I got with my kit at home.

My issue is this: the pool store recommends a level of 60-200 ppm for my 7000 gal SWG intex pool. They advised me to add 24 oz of stabilizer to reach the high end of this range. The pool school here recommends I maintain a level of 70-80 ppm. According to the pool math section, I should add 36 oz of stabilizer to get from 31 to 70 ppm.

So the pool math has me adding more than the pool store said to add to get to a number much lower than the pool store target of close to 200.

I'm very confused about this discrepancy. Any thoughts?
 
In your 7000 gallon pool it will take about 9oz by weight of CYA to add 10ppm, so 36oz would add about 40ppm to the pool.

With that said, I would trust your own testing as the CYA test is the one that pool $tores get wrong all the time.

Remember, the CYA test should be done outdoors, on a bright sunny day, with your back to the sun and viewing the vial at about waste level. Is that how you did your test?
 
Right about waist high, yes. I got to the top of the vial and still could see the dot pretty clearly. I didn't want to waste any more of the reagent testing again, because I knew the CYA was pretty low. Just put the pool up a little over a week ago and only put in 1.7 lbs to start (that's what the intex guide said to start with.) I just figured it was too low for the test to read.

So their target of 60-200 ppm is way off from the sound of it. I just thought it was odd that their program is saying to add LESS than the pool math says, to get to a much higher number than pool math recommends.

I just added 27 oz (that's all I bought today). I'll test again in a few days and see where I'm at. I want to be careful not to overshoot, since I'm starting with a pool store reading
 
With a swg I would shoot for about 70 cya. Trust pool math for the calculation. Do NOT take your cya to 200!!

Yes the cya test is tricky and can be subjective. Did your sample turn at all cloudy? If not then you have 0 or near that. If cloudy but black dot still visible at the 30 mark then between 10 and 30. You might do two cya additions to be safe. Assume you have twenty so first addition to add 50. Test after a week then one more if necessary to bring it up to 70. Overshooting cya sucks, only way to get it down is draining...
 
I agree. I'd rather have it low and gradually work my way up than overshoot and have to go through the draining hassle. With the 27 oz I added today, at least I should be up into the measurable range when I test next week. The good news is that my FC seems to be holding at 2. I'll test that every day until I get the CYA in order. After that, hopefully, I'll be able to reduce the daily run time of the SWG.
 
You can just use bleach to get the first increase in FC then let the swg handle the daily loss. Either way will work but a one time bleach addition might be easier than messing with pump and swg settings.
 
Topher55 said:
You can just use bleach to get the first increase in FC then let the swg handle the daily loss. Either way will work but a one time bleach addition might be easier than messing with pump and swg settings.
Click to expand...
You should always use bleach/liquid chlorine to raise your FC to target and then use the SWCG to maintain that FC. SWCG's are not designed to increase your FC over a short period of time.

Take care.
 

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Using poolmath you should be at about 60ppm of cya.
I have the Pool School - Chlorine / CYA Chart printed out and taped above the place I do my testing, highlighting the line that is pertinent to my pool.
The guys here on the forum and more then a few on this thread taught me this way of doing the cya test;
mix your reagent and water then shake for 30 seconds. Do you other tests fc/cc/ph, then reshake your cya test jug.
Add it to the 100 line, then holding in the proper place "glance" at the dot, if you stare at it you can see it a lot easier.
If the glance lets you see the dot, add to the next line 90, repeat, then to the next line etc. when you have a number, record it
Then pour the contents of the gradient vial back into the mixing bottle, and redo the test, the reagent/pool water mix will be good for up to 15 minutes, so you can get 4-6 tests off of one reagent dose, at the end take an average of all readings and that should be close to your cya.
I have a notepad and record anything I add to my pool, amount type etc. comes in handy down the road.
And like Dom and mknauss I have a jug of bleach in my pool shed even though I have an swg.
*edit*
I normally wait a day or two before retesting for cya, I trust poolmath and my ability to measure, the test just reaffirms it.
 
Last edited:
LFrankow said:
Using poolmath you should be at about 60ppm of cya.
I have the Pool School - Chlorine / CYA Chart printed out and taped above the place I do my testing, highlighting the line that is pertinent to my pool.
The guys here on the forum and more then a few on this thread taught me this way of doing the cya test;
mix your reagent and water then shake for 30 seconds. Do you other tests fc/cc/ph, then reshake your cya test jug.
Add it to the 100 line, then holding in the proper place "glance" at the dot, if you stare at it you can see it a lot easier.
If the glance lets you see the dot, add to the next line 90, repeat, then to the next line etc. when you have a number, record it
Then pour the contents of the gradient vial back into the mixing bottle, and redo the test, the reagent/pool water mix will be good for up to 15 minutes, so you can get 4-6 tests off of one reagent dose, at the end take an average of all readings and that should be close to your cya.
I have a notepad and record anything I add to my pool, amount type etc. comes in handy down the road.
And like Dom and mknauss I have a jug of bleach in my pool shed even though I have an swg.
*edit*
I normally wait a day or two before retesting for cya, I trust poolmath and my ability to measure, the test just reaffirms it.
Click to expand...
The advice to glance at the dot rather than staring at it is helpful. The instruction booklet that came with the kit was no help. I had to look up YouTube videos to see how to do the tests, so I appreciate any tips on testing methods. Thanks!
 
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