CYA test accuracy - lighting and eyesight variances

[Ticojpunk]

Last night I did another CYA test in the evening (it's my 3rd time doing this test), it wasn't dark out, but the sun was down below the trees so outdoor lighting just wasn't as good as the middle of the day. I discovered that seeing that black dot in the CYA tube was a little harder without the better lighting outside. It occurred to me that outdoor lighting, direct sun, vs shade, vs time of day, dusk, etc could affect your results as it's determined by your ability to see that dot. Eyesight will also be a factor. I wear reading glasses, so waist level is a tough spot for me. It's blurry with my glasses and without. So I sometimes am pretty sure I still see it, but the blur of my vision makes me question it.

What do you all do to get the best results out of the CYA test taking lighting and vision into account?

 

[Texas Splash]

What do you all do to get the best results out of the CYA test taking lighting and vision into account?

I don't use my reading or computer glasses. I just keep the tube at waist level and glance. I try not to stare intensely or make it a critical process. I either see the dot or I don't. I repeat the viewing 2-3 times. There's some wiggle room in that test anyway. But I do ensure that I do it on a fairly bright sunny day so the light can influence the testing from behind my back or over my shoulder.

 

[Texas Splash]

Oh, and my validation .... I have someone else do the test right after me to compare our results.

 

[DrewLG]

What do you all do to get the best results out of the CYA test taking lighting and vision into account?

Buy this 50ppm CYA standard solution: R-7065 CYA Standard 50ppm (2oz)

Under the lighting you'll normally use for testing CYA, perform the CYA test with the standard solution instead of pool water. Fill the tube to the 50ppm line and look down into it. What you see is what you should look for when you do the test with your pool water.

Also see what the dot looks like at 70, 60, and 40 ppm, so you'll have an idea of how much difference there is between the measurements.

 

[PoolStored]

I called Taylor a couple years ago. They recommended the strong indirect lighting and the sun to one's back. I have since compared the CYA test to CYA Standard Solution and found that the technique gave the most accurate result for that standard.

Very roughly speaking, direct overhead sunlight is around 100,000 lux, strong indirect light (i.e. shaded from the sun) is around 10,000 lux, an overcast sky is around 1000-5000 lux but varies on how overcast (which is why a bright white cloud overcast is still OK), indoors is usually < 1000 even in a bright kitchen (more typically 500 lux).

 

[Ticojpunk]

I called Taylor a couple years ago. They recommended the strong indirect lighting and the sun to one's back. I have since compared the CYA test to CYA Standard Solution and found that the technique gave the most accurate result for that standard.

Very roughly speaking, direct overhead sunlight is around 100,000 lux, strong indirect light (i.e. shaded from the sun) is around 10,000 lux, an overcast sky is around 1000-5000 lux but varies on how overcast (which is why a bright white cloud overcast is still OK), indoors is usually < 1000 even in a bright kitchen (more typically 500 lux).

Useful stuff there. Thank you.

 

[PoolStored]

CYA - Cyanuric Acid Test

Cyanuric acid (CYA) is the chemical name for the product commonly called “pool water stabilizer” … Read more…

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