Testing CYA

[Glasslaker]

Hi y'all. I recently started using the TFP method. Picked up the TF-Pro kit and testing has been straight forward, except the CYA test.

It seems pretty subjective but it's likely just a new guy, learning curve thing. My wife and I have run this test half a dozen times. I go first and get a result of 70, then hand it to her and she can see the black dot still. She adds more solution and gets a result of 50. It's been the same scenario every time so we've settled on calling it 60 for PoolMath.

It's always the same second, triple, quadruple guessing ourselves on whether or not we can kind of, maybe, definitely don't see the dot anymore.

Any tips for running this test? Do you find yourself asking "is that the dot, I think I still see it, surely I'm imagining it now"?

 

[DrewLG]

Calibrating your eye against a known reference will help a lot.

Buy this 50ppm CYA standard solution: R-7065 CYA Standard 50ppm (2oz) and mix CYA reagent with the solution instead of with pool water.

Shake, wait a couple minutes, shake again, and fill the viewing tube to the 50ppm line. Look down into it. What you see is the endpoint that 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 visible difference there is between the measurements.

 

[Glasslaker]

Thanks for the reply DrewLG. I like that idea. Having a known reference to compare against sounds way less subjective.

 

[Orion7319]

Calibrating your eye against a known reference will help a lot.

Buy this 50ppm CYA standard solution: R-7065 CYA Standard 50ppm (2oz) and mix CYA reagent with the solution instead of with pool water.

Shake, wait a couple minutes, shake again, and fill the viewing tube to the 50ppm line. Look down into it. What you see is the endpoint that 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 visible difference there is between the measurements.

I kept having to buy that because I keep forgetting what 50 looks like. Finally I realized I can just keep the mixed solution in the mixer bottle and just shake it up again when I want to use it. I obviously struggle with the CYA test as well…