Reading CYA test

[eqbob]

A little while back, as part of another thread, I seem to temper a sidebar discussion about reading the CYA test, comparison to the known sample, etc. I don't remember what the root thread was so I can't find it to find out what the outcome was.

My wife and I read the CYA results differently. Her eyes are better than mine. I 'see' (pun intended) it disappear at a higher value than she does (i.e. at a lower fill level on the column). But it is the most variable of the tests, at least to my thought process. I've always been 'concerned' about overshooting CYA and having to partial drain to resolve. We are typically about 10ppm different. I also have variability just reading the test in different days in the 'same' conditions.

Does anybody remember what happened in that thread? Or a reference to it?

My only concern is I read it as 70 and she reads it as say...40. That would be a huge FC difference and easy to go under the target in Texas August sun loads.

 

[chiefwej]

I was reading it at a higher level, until I realized that what I was seeing as the dot still showing was in fact the outline of the sticker the dot is printed on. Easy mistake if your eyes aren't good and you are straining to look for that dot.

 

[eqbob]

If you were still seeing the sticker, wouldn't that mean you were reading it at a lower level?

So have you moved to looking at the interior of the circle to define your read level?

My problem (one if them anyways... ) is the tube is so narrow that my eyes lose the focus as it starts to fill and becomes murky and you're looking at it from a distance (eye to bottom of tube)

 

[Texas Splash]

It IS the trickiest of the tests to perform. I always try to remember that 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.

When all else fails ... remember the wife is always right. Well, okay, maybe not always, but always best to be cautious.

 

[domct203]

A little while back, as part of another thread, I seem to temper a sidebar discussion about reading the CYA test, comparison to the known sample, etc. I don't remember what the root thread was so I can't find it to find out what the outcome was.

My wife and I read the CYA results differently. Her eyes are better than mine. I 'see' (pun intended) it disappear at a higher value than she does (i.e. at a lower fill level on the column). But it is the most variable of the tests, at least to my thought process. I've always been 'concerned' about overshooting CYA and having to partial drain to resolve. We are typically about 10ppm different. I also have variability just reading the test in different days in the 'same' conditions.

Does anybody remember what happened in that thread? Or a reference to it?

My only concern is I read it as 70 and she reads it as say...40. That would be a huge FC difference and easy to go under the target in Texas August sun loads.

You could always pick up a bottle of the 50ppm standard and see who's correct.

http://tftestkits.net/R-7065-CYA-Standard-Solution-p34.html

Loser makes dinner LOL

Dom

 

[duraleigh]

My only concern is I read it as 70 and she reads it as say...40

That's just not real life experience. Consistently, folks can get within 10-15 ppm on a test. If you ever get a variance of 30 ppm, I would visit the optometrist.

 

[pabeader]

My suggestion on the other thread you were asking about, was to get the 50% solution and then figure out where in your house, yard, garage, you have to be to get it to register 50%. Then use that same place to read your pool water. What you are doing is calibrating your testing to a known setting. As long as you use the same testing environment you can expect reasonably valid results.

 

[lefty51]

Hi eqbob, Dave is probably thinking, Geez it's like lefty all over again . Pabeader is right, I got the reference solution and still didn't get a 50 reading until I wandered around the property and found a sweet spot, and now I try to test there same time of day and same sun conditions.

I think you will get comfortable with the reading and feel confident your right (or probably the wifes). If the boss is happy were all happy

 

[eqbob]

When all else fails ... remember the wife is always right. Well, okay, maybe not always, but always best to be cautious.

That's largely what I do, but there are some nuances there I will try to implement and see if that improves my consistency.

As far as the wife, the saying of "I may be a lefty, but I'm always right" is a favorite of hers <LOL>

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I think you will get comfortable with the reading and feel confident your right (or probably the wifes). If the boss is happy were all happy

Yep...if momma ain't happy....ain't nobody happy <G>

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That's just not real life experience. Consistently, folks can get within 10-15 ppm on a test. If you ever get a variance of 30 ppm, I would visit the optometrist.

LOL. I hear ya. That scenario was as a potential, could it happen type of deal, not a recall of an actual situation. I do have a right eye vision problem that took away clarity at a close situation and it can't be corrected, but it hasn't been a problem yet in reading any test results. As you said, we are generally within 10.

- - - Updated - - -

My suggestion on the other thread you were asking about, was to get the 50% solution and then figure out where in your house, yard, garage, you have to be to get it to register 50%. Then use that same place to read your pool water. What you are doing is calibrating your testing to a known setting. As long as you use the same testing environment you can expect reasonably valid results.

I like that. Thanks!

 

[lefty51]

I'll just add, if she's a lefty, I KNOW she's right

 

[frbruno64]

I automatically close my left eye and use my right eye to view the dot from above, (similar to looking in a microscope or telescope.)

Does this test require both eyes to be open?

 

[eqbob]

That's just not real life experience. Consistently, folks can get within 10-15 ppm on a test. If you ever get a variance of 30 ppm, I would visit the optometrist.

We did a comparison test today and we're within 5. She read 45 I read 50.

 

[Texas Splash]

Hey! That's much closer. You are starting to read the CYA like a team. When you get that close, probably best to go with the higher number. Just like taxes - round-up over 5.

 

[eqbob]

Yep. Today will up it to the proper level.

 

[eqbob]

80 ounces in the water. Should now be at 70 next time I test.

 

[Hereinthe210]

Is there a time limit as far as the read goes. I have noticed that I "see" the dot disappear and then it seems like it reappears. I don't know if it's just my eyes adjusting or the solution settling.


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[tim5055]

We did a comparison test today and we're within 5. She read 45 I read 50.

I always test CYA when the dear wife is at home. We pour back and forth, each come up with a number and average. To be honest we are usually within 5 - 10.

 

[eqbob]

Is there a time limit as far as the read goes. I have noticed that I "see" the dot disappear and then it seems like it reappears. I don't know if it's just my eyes adjusting or the solution settling.

I believe there's a very different answer for that question depending on whether you're using liquid or solid stabilizer. The solid takes much longer to move into the water and appear. I think I recall seeing statements of up to a week past everything being dissolved? I'm not entirely sure as I've never used the solid.

The liquid says it is "instant". In practice, I wait 8-24 hours after putting it in before redoing a measure of CYA.

 

[Hereinthe210]

I just did a 80% drain refill. I used the multiple eyes (mine and daughter's) and we both came up with 45 while standing in direct sun with our backs to it holding test kit waste level. Now I am confident that the drain helped out and glad that my new TFP friends recommended the drain.


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[jstblush]

I have a question on the results. My husband and I come up with different readings sometimes also. But he holds the tube with his hand almost completely covering the sides of the tube. I hold it at the top with light getting through most of the tube. I did it his way to see what I got. It really does make a difference if the tube is mostly covered or mostly not covered with the light going through the tube. Which way is the correct way to hold and read?