Help with CYA and comparing to Standard!

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S

Snoufette

0
May 29, 2015
47
Cincinnati/ohio
Like many others I too am very frustrated with the CYA test. I feel like I am improving but to be sure I ordered the Standard to compare. I can still see the dot!!! I thought it should completely disappear!

Comparing the 50 ppm standard to my pool water tube I am measuring 80 ppm with my pool water. However I feel comfortable saying that with my pool water tube the dot pretty much disappears closer to 60. I know responses with say to go with the standard but why can I still see the dot. Its a bright sunny day.... back to sun... tube at waist level. And yes I have poured and repoured. If I move to more shade the dot is even more evident.

I would love to believe my stabilizer is at 80 because that would be perfect for my swg. But if it's 60 I need to add some. If I'm wrong and it's really 80 then it will be too high! What do I do?
 
By the way, and it's embarrassing to admit, but on 2 separate occasions, I poured the 50ppm Standard Solution directly into the viewing vial, thinking it was pre-reacted or a concoction that simulated the effect. It was crystal clear all the way to the top, and I was going to call TFT to find out why it went bad so quickly. Duh...finally figured it out that I had to add the R-0013, before I made that embarrassing call.
 
gtemkin said:
i'm not understanding what you saying. What is the measurement where the standard solution completely obscures the black dot? Is it 50, 40, 30 or never?
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It's a 50 ppm standard so it should disappear at 50 but I think I can see it. It's obscured but not gone. Using it to compare the tube that has my pool water mixture they look the same when my pool water tube measures 80. But again I don't feel that's following the instructions.
There's gotta be a better test. If it's so important to get your cya correct it seems like the test should be less subjective.
 
If there was a better test, we would use it.

You need to adjust the way you look at the test so that the standard solution gives you 50. That is the point of it. Your lighting conditions are not correct if you still see the dot.
 
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Lighting is a very much a major player. In other posts on this subject, others have pointed out that reflections in the meniscus can confuse the eye into thinking there's still a black dot. Not saying that's the case here, but I wanted to throw out the possibility.
 
I think this test can play tricks on our eyes. Now this is not scientific but ..You know how if you stare at something then look the other way you can sometimes keep seeing that object. If you look on the Taylor page about CYA test they have some photos of the test from start , mid, to finish. Try staring at the start then the mid. Then look at the finished photo and you can still see the dot, or our mind thinks it see's the dot. Now if you look at the photo's quickly it seems the dot is gone in the finished photo. I noticed this the other day when I did a test. The longer I looked at that dot it seemed to never go away but was VERY faint. I tried to just quickly do the test and it seemed more definitive to my eye's. Thought's on this non scientific way to look at it?
 
rphpool said:
I think this test can play tricks on our eyes. Now this is not scientific but ..You know how if you stare at something then look the other way you can sometimes keep seeing that object. If you look on the Taylor page about CYA test they have some photos of the test from start , mid, to finish. Try staring at the start then the mid. Then look at the finished photo and you can still see the dot, or our mind thinks it see's the dot. Now if you look at the photo's quickly it seems the dot is gone in the finished photo. I noticed this the other day when I did a test. The longer I looked at that dot it seemed to never go away but was VERY faint. I tried to just quickly do the test and it seemed more definitive to my eye's. Thought's on this non scientific way to look at it?
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I think you're on to something there and I think the effect is stronger or weaker for different people.

I know when I'm roasting coffee in a little circulating popcorn popper in the back yard and I'm staring down at this rotating mass of coffee beans, when I look over at my voltmeter that's monitoring my heater voltage, the meter numbers briefly distort and rotate - as if they're italicized. I tried to confirm that with my wife and she can't see that effect at all!
 

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gtemkin said:
i'm not understanding what you saying. What is the measurement where the standard solution completely obscures the black dot? Is it 50, 40, 30 or never?
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75b6cac1d243e8bc6c123cf8034f9143.jpg


Here is a pic of the standard solution mixed with reagent. Waist high, back to the sun, filled to the 50 ppm line. Dot is very visible. How can this be?


Sent from my iPad using Tapatalk
 
I would have to agree with the above. I ordered the Taylor test kit to compare with the TFTest Kit. Taylor shows my CYA to be higher than TFTest Kit.

So, I tried an experiment. When I used the TFTest Kit reagent with the Taylor comparitor I could see the dot all the way up - much further than when using the Taylor reagent. Also, test strips show CYA to be higher at 30-50. Why, when using Taylor reagent, does Taylor show CYA at about 35 and TFTest Kit, when using TFTest Kit reagent, shows it about 22 before you can't see the dot. Then when I substitute the TFTest Kit reagent and use it with the Taylor comparitor it shows about 22 before I can't see the dot. So, what I am saying is that there is a difference in the reagents. I'm not saying one is right or accurate and the other one is wrong, just that there is a difference. Something else, though, the strips show the CYA to be 30-50. It makes me wonder that the true CYA must be above 30.

Snoufette, I would recommend that you get some test strips (AquaChek made by Hach 100 count are a good choice) and see what they say and then, if you want some more data, go to a couple of pool stores and see what they say. CYA is not something that has to be exact, luckily and we can usually get a ball park figure and go with it.
 
jblizzle said:
So change the lighting! The dot should be gone at 50ppm.
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Well it's not.... and I've tried to change the lighting. This is actually the "most obscured" I could get.

- - - Updated - - -

chem geek said:
Dave (duraleigh) is going to check this out on Monday or Tuesday. Let's see if he finds anything wrong, possibly with the melamine reagent.
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Thanks. I appreciate your help and advice. I am in no way trying to find fault with the standard or reagent. I LOVE my kit and I love testing my water myself. I am kind of addicted. I just want to know what to do with my stabilizer. If I am not measuring it accurately how do I know if I need to add any. And how do I know what my FC should be? Just trying to figure it out. It's the only test I can't get right.
 

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