CYA and the little black dot

[Jschway]

Is there a better test for CYA? Trying to make the black dot disappear just does not seem very accurate.

 

[duraleigh]

No better test at virtually any level. It is also accurate enough for TFP requirements

 

[Oly]

What is your estimated test result? Can you identify a range? Are you between 30 and 100? What is your target CYA ppm? What kit are you using?
Remember results are rounded up to the next 10th, no middle numbers

 

[Jschway]

My friend said his CYA fluxs with every test... So my conclusion is that his eye sight is not great...

 

[jesse-99]

It's generally a very subjective test. I can test my CYA and get 30 or 35 (round up to 40), and my pool maintenance guy with his Taylor kit can get 50 with the same water sample. I think it's very particular to judgment and how the R0013 is mixed and how precise one person is versus another when it comes to how much water, and how much R0013 is added, maybe. Everyone complains about the CYA test

 

[wireform]

Get comfortable with it by pouring it back into squirt bottle and the again till you have a comfort zone with it. Do not stare at it as a simple glance will work as long as you have bright light behind your shadow.

 

[Jschway]

Adding 10 is new for me.. what's up with that? I'm assuming someone is going to post a help article.

 

[mknauss]

CYA Testing - Further Reading

www.troublefreepool.com

 

[Newdude]

I think it's very particular to judgment

There's a 50+ year age difference across membership. Then people in each age bracket have different levels of vision also.

No kidding no two of us see the same thing.

 

[DrewLG]

CYA Testing - Further Reading

www.troublefreepool.com

... and don't miss this section of that page: CYA Standard Solution

 

[ajw22]

Adding 10 is new for me.. what's up with that? I'm assuming someone is going to post a help article.

You round up to the nearest line, not add 10.

The scale is logarithmic, not linear, and you cannot eyeball values in between the line. If the dot disappears to you between the 40 and 30 lines you simply call it 40 and move one. Don’t agonize about precision in that test. +/- 10 ppm rounded up works fine for the purposes of the test.

 

[Decoy205]

To be clear, when people here say “glance” they mean look quickly and then look away correct? If you do that while holding the tube chances are the water is moving a bit and you won’t see the dot.
If you do it with the tube sitting on a table the still water maybe will make it easier to see the dot even at a quick glance.

I guess I want to confirm how people conduct the “glance” part.

 

[Newdude]

I look away and then look back down. I call it from the first flash of a glance. I dunno if it's from being cross eyed or a reflection from light bouncing down the tube, but I see a faint darker area in the middle that isn't the googely eye if I stare.

 

[ajw22]

I move my head and eyes when I glance, not my hands.

 

[Supersix]

I felt the same way pool math recommended I add 2lbs. I waited a week and tested the water the dot was visible at 30. I added another 2lbs 3weeks later it was reading 40 I hit it again with another 2lbs and my dot disappeared and it's reading 70.I had a great teacher @Newdude .He told me be patient you don't want to add to much stabilizer let the pool circulate for a week and add a little at a time you will get there.

 

[farmy87]

...but I see a faint darker area in the middle that isn't the googely eye if I stare.

I've been having this same issue this summer, annoying!

 

[sarturo]

You round up to the nearest line, not add 10.

The scale is logarithmic, not linear, and you cannot eyeball values in between the line. If the dot disappears to you between the 40 and 30 lines you simply call it 40 and move one. Don’t agonize about precision in that test. +/- 10 ppm rounded up works fine for the purposes of the test.

If you really want to split hairs you can eye ball it slightly. 1/4 between the numbers would be about 1.78 ppm (round to 2), 1/2 would be 3.16 ppm (round to 3) and 3/4 would be 5.62 ppm (round to 6). Just use the 10^x with x being fraction you approximate between the lines. Should add this is easier to do with the large tube that reads down to 20ppm CYA.

 

[Newdude]

If you really want to split hairs

I want less work, not more. The lazy is strong with me.

 

[ajw22]

If you really want to split hairs you can eye ball it slightly. 1/4 between the numbers would be about 1.78 ppm (round to 2), 1/2 would be 3.16 ppm (round to 3) and 3/4 would be 5.62 ppm (round to 6). Just use the 10^x with x being fraction you approximate between the lines. Should add this is easier to do with the large tube that reads down to 20ppm CYA.

It buys you nothing in the TFP Pool Care Methods to have that precision.

 

[BMerrill]

Not seeing it mentioned above.
Fill the tube to say the 100 line, take a look.
Did you see the dot?
Yes, fill to the next number line and repeat the glance.
Continue until the dot is no longer visible.
I find this much easier then gradually filling the tube.