Is there a more accurate cya test than the Taylor kit?

[ramirez41]

Is there a more accurate way to test cya? I really struggle with the cya test. I can get big range in the test with my Taylor test kit. I make sure I mix for 30 seconds, have my back to the sun, I am holding it at my waist, glance away to insure my eyes are not seeing an imaginary dot. I can get different reading wheel using the same solution and I reshake it before retesting. I get a range from 40-60. Are the pool store tests more reliable for cya?

 

[mknauss]

No.

 

[PoolStored]

No. +

 

[JoyfulNoise]

Yes … if you’re willing to pay hundreds of dollars for a digital photometer along with all the calibration standards and extra hardware needed … and then have it factory recalibrated every year or so.

So … practically speaking … no.

 

[ajw22]

You don’t need a very accurate CYA level. +/- 10 ppm is fine and then round up.

 

[generessler]

As @mknauss has pointed out before, accuracy isn't a huge deal. 40 or 60 means target FC is 5-7 or 7-9, and the absolute min, where you'd be in danger of algae, is 3. So shoot for 7. All good. nb: you should "invert the bottle repeatedly," not shake it hard. I guess that could add air. For fun you can order a standard CYA=50 solution from TF Testkits and practice.

 

[Donldson]

Small thing perhaps, but accuracy means how reliably it shows the correct answer within the margin of error. Precision is how specific the answer is.

The FAS-DPD test is accurate and precise. It consistently can give you a reliable answer to +/- 0.2 ppm FC (when using the 25 ml sample).
The CYA test is accurate but not precise. With proper lighting it reliably gives you a correct answer but within a fairly large margin.
Pool store machine testing is not accurate but precise. The result is not reliably correct, but it provides very specific numbers.
Test strips are neither accurate nor precise. The results are not reliable and the color matching is very imprecise.

So no, the CYA test is the most accurate test that is reasonable to own given the ease of overcoming the imprecision of the test.

EDIT: small grammatical improvements

 

[Jimrahbe]

41,

I have a "Sliding dot CYA tester" that I like better... It is no more accurate, or precise, than the Taylor kits, but it works better for me..

If you are looking for something that is perfect, this is not it..

I like that I can move the dot up and down and find 'my' sweat spot.. But, It is still pretty subjective.

I try to run the test the same way every time, so that even if my answer is not precise, it is close to the same every time..

Amazon.com

Thanks,

Jim R.

 

[JoyfulNoise]

Do you have the 50ppm CYA Standard solution?

I have often checked my eyeballs and lighting by using the standard solution. Since it’s known to be 50ppm, you mix it up with the reagent and then fill the tube to the 50ppm mark. Then you go outside and look at the tube. Find the best lighting and distance from your eyeballs that gives no dot at 50ppm. It’s a good way to check yourself and gain confidence.

Make sure you’re following the directions with regard to holding the tube properly and at the proper distance from your eyes as well as not staring intently at the tube forcing your brain to “see” a dot.

It’s not the greatest test but it’s generally close enough for what is needed.

 

[flynwill]

Yes … if you’re willing to pay hundreds of dollars for a digital photometer along with all the calibration standards and extra hardware needed … and then have it factory recalibrated every year or so.

I assume it would also be possible to get a more accurate reading by filtering and weighing the precipitate from the test. (With suitable lab equipment to weigh the inputs, filter paper before filtering, etc). I vaguely remember doing such an analysis back in chemistry class.

(But agree with all the others hardly worth the effort).

 

[JoyfulNoise]

I assume it would also be possible to get a more accurate reading by filtering and weighing the precipitate from the test. (With suitable lab equipment to weigh the inputs, filter paper before filtering, etc). I vaguely remember doing such an analysis back in chemistry class.

(But agree with all the others hardly worth the effort).

Not really. The melamine-cya precipitate can be quite complex in its long range structure and so you’d have to have a way to know how much melamine was added to the reaction and when to stop. The current test simply uses an excess quantity of melamine to react with all of the unknown amount of CYA and then infers a concentration based on optical occlusion.

Somhoet of some very expensive lab equipment that takes graduate students to run it, the poolside analysis of CYA is always going to be course at best.

 

[ramblinwreck001]

I echo @Jimrahbe, I like the Blue Devil B7525 kit better than the Taylor-based CYA test that came in my TF-Pro kit. I find the larger quantity and the "sliding dot" makes it easier to get consistent results. Some people complain about the expense of consuming more reagent, but I just got an 8oz refill for $13 and that will last me the season so IMO that cost issue is overblown.

I have used the Blue Devil and TF-Pro CYA test side-by-side a few times and I cannot get consistent results from the TF-Pro one (even with their standard solution).

 

[generessler]

Fwiw I use the 50 ppm solution and violate the rules somewhat because I'm very nearsighted. I fill to 50, then intentionally bring the test vial close to my eye. I can still see a shadow of the dot. With a little practice, the look of that shadow is much easier for me to discern than the "glance down at your waist" method. I test myself by adding a mix with the 50 ppm solution, not looking at the scale, until the dot looks right, then verify I'm actually close to 50. This way, it's easy to get within 10. Standard lighting is still very important, though.

 

[sande005]

I used the LaMotte version of the sliding dot for years. It still is subjective, but seemed slightly easier. In head-to-head with Taylor, it gave the same end result. It does require their tablets, that take forever to dissolve. Or need a pill crusher to break them up after dropping into the water sample.

One can get just the hardware on Amazon, if interested. I never tried it with the Taylor mix, so using same may not be accurate at all. The dot on mine finally wore off, so now I just use the tube that tftestkits supplies.

Cyanuric Acid Test Kit

 

[Jimrahbe]

Gene,

I think what you are doing makes perfect sense.. You making sure you run the test the same way every time.. And then looking at the result.. Even if you are slightly high or low, it does not matter, as normally you are just trying to see where you are now vs. where you were at the last test.

Thanks,

Jim R.

 

[ramirez41]

Do you have the 50ppm CYA Standard solution?

I have often checked my eyeballs and lighting by using the standard solution. Since it’s known to be 50ppm, you mix it up with the reagent and then fill the tube to the 50ppm mark. Then you go outside and look at the tube. Find the best lighting and distance from your eyeballs that gives no dot at 50ppm. It’s a good way to check yourself and gain confidence.

Make sure you’re following the directions with regard to holding the tube properly and at the proper distance from your eyes as well as not staring intently at the tube forcing your brain to “see” a dot.

It’s not the greatest test but it’s generally close enough for what is needed.

Is there a number for the 50ppm cya standard test? That maybe my issue. I don't have the confidence that I am measuring it right. It seems like there could be a lot of variables that impact the test. I struggled last summer too, but were working on getting the cya down and I knew it was quite high. We did several partial drains last year and ended the season with about 70 and then drained it down about 25% for the winter. This year I think we are within range. I ended up recording 45. I did the test a couple times with the same solution and I mostly came up with 40 or 50 but did get 60 once. It was cloudy out with the sun peaking through at different brightnesses.

 

[sande005]

R-7065 CYA Standard 50ppm (2oz)

There are other standard samples too, but unless you have trouble with colors, likely not needed.

 

[proavia]

Is there a number for the 50ppm cya standard test? That maybe my issue. I don't have the confidence that I am measuring it right. It seems like there could be a lot of variables that impact the test. I struggled last summer too, but were working on getting the cya down and I knew it was quite high. We did several partial drains last year and ended the season with about 70 and then drained it down about 25% for the winter. This year I think we are within range. I ended up recording 45. I did the test a couple times with the same solution and I mostly came up with 40 or 50 but did get 60 once. It was cloudy out with the sun peaking through at different brightnesses.

If you somehow think your CYA is at 45, it gets rounded up to 50. The only viable readings are those listed on the testing tube. Any result between the lines gets rounded up to the next multiple of 10 on the testing tube.

For the CYA test, mostly better to error on the high side when in doubt. This will equate to having the FC a little higher than using a lower number for CYA. Best to have FC a bit higher than lower.
FC/CYA Levels
Always dose to the high side of the listed range as well.
Never let FC flirt with minimum.