CYA Test Confusion

[Tjcervenka]

I’ve tested via liquid my CYA and have never seen anything below 100. I so wish there was a more definitive test like counting drops. I’ve also tested using two different strips and they both come back 50. I tested the strips with tap water and they correctly showed “0”.
Which should I trust? Makes a huge difference in my FC target range. Thanks for your thoughts.

 

[Texas Splash]

Welcome to TFP! Test strips are horrible. Which test kit (liquid) are you using?

 

[Richard320]

The turbidity test is unfortunately the best.

Try this: mix up the sample, then pour it in the view tube to the 100 line. Then go stand on the patio in full sunlight and hold the view tube just at the very top with thumb and forefinger at waist height and look down. Do you see a dot? If you do, then [pour the sample back into the mixing bottle, swirl it a bit and then fill the view tube to 90 and try again. Repeat until the dot disappears. There's no shame in pouring it back and forth to be sure of what you're seeing. Bright lighting is essential. I get a different reading if I hold the tube normally, like a beer can, because my fingers block a lot of light.

And if it really bothers you, you can order a CYA standard solution and figure out what combination of light and distance has you read it correctly and then use the same technique with your pool sample.

 

[mguzzy]

Welcome to the Forum!

@mknauss has a great suggestion. He fills the tube to the lines and reads it there. Since the test only has a resolution of 10, there is no point in trying to read 12.45646. It's either 10 or 20 or 30... so fill the tube to those graduations and check the dot from there.

 

[Tjcervenka]

Welcome to TFP! Test strips are horrible. Which test kit (liquid) are you using?

The TF-100 with the reagent R0013

 

[Tjcervenka]

The turbidity test is unfortunately the best.

Try this: mix up the sample, then pour it in the view tube to the 100 line. Then go stand on the patio in full sunlight and hold the view tube just at the very top with thumb and forefinger at waist height and look down. Do you see a dot? If you do, then [pour the sample back into the mixing bottle, swirl it a bit and then fill the view tube to 90 and try again. Repeat until the dot disappears. There's no shame in pouring it back and forth to be sure of what you're seeing. Bright lighting is essential. I get a different reading if I hold the tube normally, like a beer can, because my fingers block a lot of light.

And if it really bothers you, you can order a CYA standard solution and figure out what combination of light and distance has you read it correctly and then use the same technique with your pool sample.

Thanks. The standard solution may help give me piece of mind that I’m doing the test correctly.

 

[Tjcervenka]

Ok. Now I’m really messed up. I use the R-0013 CYA reagent on a 50ppm CYA Standard I purchased (R-7065). I could still see the dot at the 30 line but not at the 20 line. Held at my waist in bright sunlight. Now I don’t know what to make of any of my results. My pool reads over 100 and the 50 standard reads 20.
Any ideas?

 

[mknauss]

That seems to be more variance than it should be.

Did you keep the mixed sample? Try the test over and over with the same sample. Want to be sure it is well mixed and has had time to develop the melamine solution.

 

[Tjcervenka]

I didn’t but I will retest. I shook it for a solid 30 seconds.

 

[Tjcervenka]

Just remembered I barely had any left because my test filled to the 20ppm line

 

[Tjcervenka]

Same result but I poured the sample back into the fill bottle and will wait for 5 more minutes.

 

[Tjcervenka]

Just waited a solid 5mins and I could still see the dot at the 30ppm line.

 

[mknauss]

Just to confirm

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

Be sure you are following the steps in that article. Also review the Notes.

 

[revitup]

It's been suggested that shaking the sample could entrain air which could skew the results. A gentle mixing is all it needs.

 

[Tjcervenka]

Just to confirm

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

Be sure you are following the steps in that article. Also review the Notes.

Followed it precisely. When I turn my back to the sun, the dot is still visible at the 40 line but not at the 30 line. This improves the variance I guess. I just noticed the notes about using tap water and doubling so I can try that.

 

[mknauss]

Do not do the dilute.

Not sure what to say. Be sure you are just glancing for the dot. If you stare down the tube, you will see it.

 

[Tjcervenka]

I appreciate your advise and help. Glancing does help as if I stare at it, I think my mind can add the dot. At the end of the day, I’ll assume my CYA is 100. My pool has looked amazing so I should leave well enough alone I guess.