Sample CYA 50ppm from TFTestKits

bobhatfield · Sunday at 10:53 PM

[Update: My technique was wrong - tftestkit 50ppm CYA sample was a big help. See my follow-up post below if interested in this subject; otherwise ignore this post.]

I purchased a bottle of CYA 50ppm water sample from tftestkits and did the block dot tests several times as a sanity check. Fail. The dot was clearly visible at 50ppm (at the "half way" mark). My reading came closer to 20-30ppm.

I'm going to reach out to them to be sure I'm doing this right (following all instructions here and on their site) and/or to find out if the sample may have been bad.

I don't want to whine about the CYA test here; I get the variances in eyes, lighting, etc., this is just an FYI in case others have tried this route to check your block dot skills.

Standard Sampler

tftestkits.net

My results:
Black dot test with CYA 50ppm sample: I get around 20-30ppm
Black dot test with my pool water: 60ppm (all other tests (FC/CC, pH, CH, TA etc.) within proper ranges)
Leslie's pool store test with my pool water: 78ppm <-- this was just for fun, I was comparing all of my tests to theirs for fun (mostly for salt before my refills arrived) but ignoring theirs.

Bperry · Sunday at 10:56 PM

bobhatfield said:
I purchased a bottle of CYA 50ppm water sample from tftestkits and did the block dot tests several times as a sanity check. Fail. The dot was clearly visible at 50ppm (at the "half way" mark). My reading came closer to 20-30ppm.

I'm going to reach out to them to be sure I'm doing this right (following all instructions here and on their site) and/or to find out if the sample may have been bad.

I don't want to whine about the CYA test here; I get the variances in eyes, lighting, etc., this is just an FYI in case others have tried this route to check your block dot skills.

Standard Sampler

tftestkits.net

My results:
Black dot test with CYA 50ppm sample: I get around 20-30ppm
Black dot test with my pool water: 60ppm
Leslie's pool store test with my pool water: 78ppm <-- this was just for fun, I was comparing all of my tests to theirs for fun (mostly for salt before my refills arrived) but ignoring theirs.

Try posting a picture here of the test sample.

PoolStored · Sunday at 10:59 PM

You need to follow these instruction. Light is VERY important. Without outdoor light, your results will be low as the CYA test is a turbidity test dependent on light.

Follow the instructions carefully...

CYA - Cyanuric Acid Test

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

www.troublefreepool.com

Bperry · Monday at 6:41 AM

PoolStored said:
You need to follow these instruction. Light is VERY important. Without outdoor light, your results will be low as the CYA test is a turbidity test dependent on light.

Follow the instructions carefully...

CYA - Cyanuric Acid Test

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

www.troublefreepool.com

Also make sure you’re mixing the 50ppm standard with your reagent in the kit. The standard is not pre-mixed and so it needs the reagent to react wjth.

Donldson · Monday at 6:55 AM

You didn't fail anything, you confirmed your lighting and/or technique was not correct.

Mix the standard with the CYA reagent, fill your view tube to the 50 mark, and play around with lighting and positioning of the tube until you cannot see the dot. That's the lighting and positioning to use to get an accurate reading.

duraleigh · Monday at 7:28 AM

Taylor bottles that 50 ppm sample in pretty large quantities and it doesn't "go bad", so, it is not likely to be a 50 ppm issue as other purchasers would report it as well. It is a hard test to master and impossible to get perfect each time. Good advice above. TFTestkits uses most all Taylor chemistry because of their consistency

bobhatfield · Monday at 12:21 PM

Donldson said:
You didn't fail anything, you confirmed your lighting and/or technique was not correct.

Mix the standard with the CYA reagent, fill your view tube to the 50 mark, and play around with lighting and positioning of the tube until you cannot see the dot. That's the lighting and positioning to use to get an accurate reading.

Boom! Thank you! (thank you all) Why I ignored the "stand with your sun at your back" all these times, I'll never know. That did the trick - the extra lighting made the solution appear less translucent.

Filling the tube to the 50 mark, then moving to where the dot disappears, was excellent advice.

FWIW, Because of the 50pmm sample and working with it, I also now know to ignore the "larger black dot" I was seeing - that's thrown me off in the past. That's sort of a phantom black dot that may be the bottom of the tube or an optical illusion.

Anyway - all good now, thanks again guys! I also corrected my first post.

Newdude · Monday at 12:54 PM

bobhatfield said:
That's sort of a phantom black dot that may be the bottom of the tube or an optical illusion.

Did you stare? Your brain lies if you stare. It has to be a quick glance. Like. Lightning quick. I look away, then back and call it that instant yes/no.

You can also pour back and forth as many times as you need for best of 3, best of 7, Man i hate this test. :laughblue: