Better way to test CYA?

[IUsedToSail]

Are there any methods to test CYA outside of using the "drop test" method with the black dot? I am struggling with it as it seems pretty subjective.

About a month ago I accidentally dumped some stabilizer in my pool instead of calcium hardness increaser. I was pretty upset over it and my CYA bumped up to about 100 per my TFP test kit; the pool store's ALEX testing system came up with about the same number. I drained a little water from the pool and filled via our well. We've had a ton of rain over the past two weeks and the water level is really high. When I tested over the weekend the CYA seemed to be down to at least 80 possibly as low as the 65. However, I'm a little skeptical of the results as I just don't feel very confident around exactly when the dot disappears.

I

 

[HermanTX]

The best way I have found to test CYA is as follows
After making the mixture
Pour the solution in the tube to a known level i.e. 100
then look for the dot - if you can see it
pour the solution to the next level - 90 - can you see the dot?
continue in these 10 unit increments until you cannot see the dot
Your CYA level is the one before you could not see the dot - the higher number - if you could see the dot at 40 level but cannot at 30 then the CYA is 40.

This helps in that you are not constantly looking at the dot as you pour in the solution - you get too dot focused if you watch & pour at the same time
You only glance at the bottom of the tube and if you see the dot then continue on to next increment
Also, you will not be trying to figure out if the CYA is between 2 levels. Since this is a logarithmic scale, you really can't make assumptions on the value between 2 lines. This is why your CYA should always be reported in decade units, 30, 40, 50, etc.

Also best to do with back to sun. Try to avoid doing it inside unless you have sun shining in through window.

Hope this helps.

 

[IUsedToSail]

The best way I have found to test CYA is as follows
After making the mixture
Pour the solution in the tube to a known level i.e. 100
then look for the dot - if you can see it
pour the solution to the next level - 90 - can you see the dot?
continue in these 10 unit increments until you cannot see the dot
Your CYA level is the one before you could not see the dot - the higher number - if you could see the dot at 40 level but cannot at 30 then the CYA is 40.

This helps in that you are not constantly looking at the dot as you pour in the solution - you get too dot focused if you watch & pour at the same time
You only glance at the bottom of the tube and if you see the dot then continue on to next increment
Also, you will not be trying to figure out if the CYA is between 2 levels. Since this is a logarithmic scale, you really can't make assumptions on the value between 2 lines. This is why your CYA should always be reported in decade units, 30, 40, 50, etc.

Also best to do with back to sun. Try to avoid doing it inside unless you have sun shining in through window.

Hope this helps.

Yes, that is a great suggestion, thanks!

 

[mknauss]

Also, pour the solution from the test vial back to the dropper bottle and do the test multiple times.

 

[PoolGate]

Buy the reference 50 ppm solution so you know what to look for!

R-7065 CYA Standard 50ppm (2oz)

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