TF-100 CYA test, when to stop filling the CYA tube?

[Cain]

I have probably a simple question but I just want to confirm.

When filling the CYA testing tube, when do you truly stop.

I know that sounds odd, but is it when:

- dot is fully gone while pouring
- dot fully gone after a swirl on the water
- dot starts to dissappear

Also, I am assuming when pouring you don't want to have some much pressure you bubble up in the tube, that seems to affect clarity of the dot I am seeing even when the bubbles seem to go down.

Right now it looks like depending on if its after a swirl or only on the pour itself, a difference of almost 10 - 20 CYA so curious.

 

[Texas Splash]

You want to squirt the pre-mixed (bottle) solution into the skinny tube fairly easy and steady. You also want to ensure the black dot completely disappears. Once it's gone, that's your CYA.

Proper lighting is important for the CYA test. You want to test for CYA outside on a sunny day, but keep the skinny view tube in the shade. Taylor recommends standing in the sun with your back to the sun and the view tube in the shade of your body. Use the mixing bottle to combine/mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then mix again. Then, while holding the skinny tube with the black dot at waist level, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. After the first test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate the CYA reading.

 

[Divin Dave]

yup. When the dot is disappeared. As you prolly found out, sometimes its hard to tell. what I recommend is when you think the dot is gone, pour teh solution back into the mixing bottle and repeat the test, then repeat it again and use the 'most common' number as your CYA test.

Due to the subjectivity of peoples eyesight, and the effects of lighting conditions and what not, the CYA test considered accurate to 10ppm.
so, it looks like you're in the ballpark.

 

[Cain]

thanks everyone! I tried this a few times here and I think I am getting the hang of it. Pretty much fill till I see the dot gone, then I do the retest by pouring it back in as suggested.

From that I am seeing consistent (at least to me) results. Thanks!