Testing CYA

Shocktop2000

Member
Jul 16, 2019
13
Houston, Texas
I use the Taylor kit. The process is where you add 7 ml of pool water to 7 ml of the CYA reagent. You then slowly fill the container until "the dot just disappears." Here is my issue. I feel like I can always see the dot at full, meaning CYA is less than 30. I have been adding pucks in the dispenser to get CYA in the 50 range. The water gets more cloudy on the test, but I can always see the dot. It just gets harder to see.

I wanted to inquire about reading this test. When your CYA is 50 does the dot entirely disappear at the 50 mark? Or does "just disappear" mean it is difficult to see?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,721
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
It should look like this -


Let me ask you a process question - when you add the reagent to the water sample, are you gently inverting/mixing it for 30sec then letting it sit for 30sec, then inverting it to much once and dispensing into the view tube?
 

DanF

Silver Supporter
Mar 17, 2019
350
Chandler, AZ
I have the same issue with the dot never quite disappearing.. Just read the CYA link. It didn't say anything about waiting 30 seconds before testing. Should we be?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,721
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I have the same issue with the dot never quite disappearing.. Just read the CYA link. It didn't say anything about waiting 30 seconds before testing. Should we be?

I invert/mix for 30 then sit for 30. Sometimes air bubbles form in the solution, especially if people shake it up vigorously, and entrained air bubbles can mess up the test. Before I dispense it into the tube, I invert one more time just to make sure the particulates formed are mixed in the solution.

I never have issues seeing the dot disappear.

Are you also doing the test outdoors in bright sun with your back to the sun and tube held waist high in the shadow of your body? And your hands and fingers are not blocking the tube? You should be holding it by pinching it at the top leaving the tube open to incoming light.
 
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Shocktop2000

Member
Jul 16, 2019
13
Houston, Texas
It should look like this -


Let me ask you a process question - when you add the reagent to the water sample, are you gently inverting/mixing it for 30sec then letting it sit for 30sec, then inverting it to much once and dispensing into the view tube?
Thanks for the response. I shake it vigorously for 30 seconds and then start adding it to the tube. I will try to slowly invert for 30 seconds, let it sit, and then conduct the test. Thanks!
 

markayash

Gold Supporter
Mar 21, 2016
2,966
Atlanta Ga
Taylor Kit just says shake for 30 seconds..I also had the TF kit and it said shake and let sit so I still do that
You should get to a point where it really hard to see..If it's clear to the top you probably don't have an CYA..Try it with just plain tap water then use you mixture and compare them
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,721
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
So this is one of those issues that Taylor doesn't clearly explain and people often mistake. For what it is worth - you should NEVER vigorously shake any chemical solution.

The reason being is that shaking a solution violently will entrain small air bubbles in the water and they can take a long time to dissipate. Microscopic entrained air bubbles will mess up the visual effect needed by changing the way light scatters in the tube. Also, for pH, shaking violently is bad because that approximates the effect of aerating the water sample. Aerating a water sample will cause the pH to rise and give false-high results.

There is never a need to violently shake the chemicals. Simply invert to mix, or hand swirl, and that will do more than enough. Or, better yet, get a SpeedStir.
 
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