TF-100 CYA control test issues

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Stockhatch

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Nov 7, 2015
7
Wilmington NC
The control sample that came with my TF kit seems to test closer to 30ppm. I can clearly see the dot still at 50ppm. On the plus side, the kit allowed me to determine that my CYA is the cause of my algae issues, as it is off the charts. I will be draining to clean some existing staining anyway, but I was a bit concerned that my very first test (using the control sample) seemed so far off. Is this common?

Thanks!

Adam
 
Some people get better results with the glance method. Look away from the tube, then glance at it. Look away, glance again. If you see the dot, keep adding, but if you don't see it with a glance, you're there.

Great that you have the standard. That provides a way to fine-tune your method. And don't be alarmed, everyone finds the CYA test to be a bit tricky.

Also, you can pour the test solution back into the mixing bottle, give it a shake and then test again. Some people do it three times and have a better idea.

- - - Updated - - -

There's a few other tips as well. Have the sun to your back, hold the tube in the shade at waist height and look down. Be sure your sample is warm enough, but I'm guessing that isn't an issue just now. It should be around 75 or warmer.
 
Thanks all. Yes, the dot is VERY clearly visible whether glancing or staring, regardless of distance or lighting. It's just plainly visible until 30ppm. There is nothing else I can really say. I can take pics to show what I am seeing, but I have seen pics online of obscured dots, and I am very confident that I know what to look for. My pool sample completely obscured the dot well before reaching 100 even. Regardless, I know now that a drain is absolutely required, so the test kit was well worth the investment. Strips were really lying to me about my CYA. :)
 
Stockhatch said:
The control sample that came with my TF kit seems to test closer to 30ppm. I can clearly see the dot still at 50ppm. On the plus side, the kit allowed me to determine that my CYA is the cause of my algae issues, as it is off the charts. I will be draining to clean some existing staining anyway, but I was a bit concerned that my very first test (using the control sample) seemed so far off. Is this common?

Thanks!

Adam
Click to expand...
Your tf kit came with a control sample?
 
Bullet #8 that is in the "what's included" section:

R-7065 CYA Standard Solution test-Over the years we have found that testing for CYA is often times confusing to many individuals. R-7065 is basically pool water with a result of 50 ppm CYA. It allows you to test the effectiveness of your R-0013 and to ensure you are using proper testing techniques
Click to expand...
 
Countpyro1 said:
Your tf kit came with a control sample?
Click to expand...

This is a new offering from TFTestKits. The newest version of the TF-100 comes with a few test's worth of the R-7065 solution which is a 50ppm CYA standard. I believe this newly modified kit has been shipping for the last month or so.
 
Make sure you shake both the R0013 and the R7065 before use....I definitely notice a difference. I was getting the same ~30 CY with the benchmark. I did a test immediately after this, but shaking both solutions well, and it came in close to 50....whether it SHOULD make a difference or not, I don't know, but it did for me....
 
Thanks for the feedback.

Yes, as Matt indicated, it is a new feature, upgrade to the TF-100 in the last month or so. The theory of the sample is that, if mixed and tested properly, this is a known 50 ppm sample. This is what 50 ppm of CYA looks like. Train your eye to look for this end point in the test. TFTestkits is rolling out some samples to some folks so we can better understand how it works and how to help people with it.

Here are some reference photos of the test from Taylor
https://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=36
 

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By the way, the correct way to use this standard is to make up the mixture with the R-0013 and then fill the view tube to the 50ppm mark. Then you go around your property or house and find the correct lighting and viewing conditions that makes the dot disappear. Then, when you actually test your pool water, you use the same conditions from the test.
 
I'll try again after shaking the sample up well. The dot would have been visible in any light conditions. It looked very close to "mid test" in that example picture. I am in the process of acid cleaning the pool and converting to SWCG, so it will be a little while before I can test my pool water again.
 
JoyfulNoise said:
By the way, the correct way to use this standard is to make up the mixture with the R-0013 and then fill the view tube to the 50ppm mark. Then you go around your property or house and find the correct lighting and viewing conditions that makes the dot disappear. Then, when you actually test your pool water, you use the same conditions from the test.
Click to expand...

Thanks for this. I have struggled between seeing what I *think* is the dot and what are actually reflections / shadows on the inside of the vial. I'm going to try this today, as I think it's purely lighting related.
 
JoyfulNoise said:
By the way, the correct way to use this standard is to make up the mixture with the R-0013 and then fill the view tube to the 50ppm mark. Then you go around your property or house and find the correct lighting and viewing conditions that makes the dot disappear. Then, when you actually test your pool water, you use the same conditions from the test.
Click to expand...
Good idea. Now I need to try this
 
I was going to create my own thread and then found this one which sums up my issues quite nicely. I hope everyone doesn't mind if I piggyback. I too am having issues with inconsistency even with the standard. Below are some pics with R-7065, which I based on my testing read 25. The pics in order are: visible dot at 55, visible dot at 50, visible dot at 45, and the last two show a vanished dot (even though I can still slightly make it out) and the corresponding reading. I know lighting is not an issue. My backyard is shaded in the evenings when this test was done and it was cloudy out. Perhaps I'm doing the test incorrectly. The instructions say mix and wait 30 seconds. I've seen elsewhere where you actually mix for 30 seconds. Which is it? I have no clue what my pool CYA is as I've blown through the R-0013 and R-7065 trying to get this right. Any suggestions would be appreciated.

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For me, when I decide to test for CYA, I mix it up first. Shake for 30 seconds, then stick it in my pocket. Then I complete whichever other tests I plan to do. Then pull out the CYA bottle and shake it a bit, then do the test. Works for me, but I can't speak for this as a recommended method, other than to say I read it here and no one said it was a bad idea.
 
swing4terps - couple notes:
- The lighting does not look bright enough (no sun out?)
- You should try holding the vial at the very top with only 2 fingers so that more light can hit the solution.


That said, it seems that just about everyone gets a reading closer to 40 than 50, unfortunately.
 
jblizzle said:
swing4terps - couple notes:
- The lighting does not look bright enough (no sun out?)
- You should try holding the vial at the very top with only 2 fingers so that more light can hit the solution.


That said, it seems that just about everyone gets a reading closer to 40 than 50, unfortunately.
Click to expand...

Oh, I always thought the idea what to eliminate any sunlight while doing the test hence turning your back to the sun. I guess I will need to buy more R-7065 and R-0013 and try these alternative methods.
 
Yeh, what Jason said just turned on the lightbulb for me too. The lighting needs to be bright enough to light up the particles floating around so they obscure the dot!! But not super bright direct sun which wouldn't work. Thanks so much!!!
 

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