CYA Testing Help

Jump to latest Follow Reply
7Iron

7Iron

0
LifeTime Supporter
Jun 14, 2014
71
Mobile
Yesterday I received 8 oz of each the R00013 and the 50ppm test solution from TFTestKits. I have used just about half of the solutions in about 6 different attempts to calibrate my reading at 50ppm.

All of the samples keep reading at 30 or just a smidgen above 30 using the large tube that came with the kit. I tried adjusting the top of meniscus to bottom of the label and the bottom of meniscus to bottom of the label with No appreciable change in reading, all samples read somewhere very close to the 30 ppm line.

The 2 pics are the last sample (no different than previous samples) with the solution at the 50ppm line.

One pic has the camera light on, and one with out light.....the pic with the light on is closer to the actual image at waist level, outside, with back to 9:30 morning sun, cloudy day.

In both pictures the dot is clearly visible. What the heck am I doing wrong???



What the heck am I doing wrong?
 
Last edited:
thanks JasonLion,

After depleting 2/3 of the 8oz bottles of 50% and R0013 solutions, and altering mixing times, meniscus levels of test solution, and filling levels of r0013 , all tests were essentially the same at 30ish.

I tried filling the R0013 to the bottom of the mixing bottles shoulder(top of the label) and then up to the top of the shoulder (bottom of the bottles neck). .

All mixing times were: 30s mix, wait 60s, and mix 10s and read....No change from yesterdays mixing of: mix 30s, wait 30s, mix 30s and read


All readings(from using 2/3 of the test solution) were around 30 ish with the majority at what I would call 32... I believe the variability around 30 is due to my subjective reading....

I have to conclude the test solution is 30 not 50 when read in the large tube provided with kit or I am a complete dunce.

Interestingly, during the 2nd wave of calibration testing, I would use the solution that I mixed in the TFTestkit large mixing bottle in the Taylor R2006 comparator and would get 50ppm ish every time. I also used the test solution and TF reagent with the Taylor K2006 mixing bottle and also got 50ish. I also used Test solution and reagent from Taylor kit and k2006 comparator ....and it yielded 50ish...(plus or minus meniscus or just a drop or two---I believe a reading variation)

I do not know what I am doing incorrectly. The $31 for the CYA Test Kit was a waist.

I have to conclude (given that the test solution is 50ppm??) the TFTestKit Comparator is unreliable. Or given the tube isnt the problem, the test solution isn't 50 but 30ppm. The difference between 30 and 50 is not a reading or mixing issue.
.

.
 
Alright, something is going wrong, but we can greatly narrow down what. First, the calibration solution is very reliable. It's level has reliably been 50+-1 for many many people over years. If there was something wrong with the calibration solution I would expect to hear about it from many people. Second, it seems you now have a reliable testing method: "I mixed in the TFTestkit large mixing bottle in the Taylor R2006 comparator and would get 50ppm ish every time". If I am reading that correctly, that is the test method you should use going forward. Third, if I followed everything correctly it seems likely there is something wrong with the view tube you got from TFTestKits. The way I read what you wrote, the TFTestKits view tube always read 30, while the K2006 view tube read 50, even while everything else remained the same. It is possible for there to be manufacturing defects in the view tube. That is very very rare, but has been seen before.
 
JasonLion,

I have another test solution (my pool)...it has been tested by 2 local pool stores (multiple times) and my self (using K2006) multiple times (posted in "CYA off the chart") at 90-100.

I used the same alternate test methods described above(3 different times) and I consistently get 100ish using the K2006 comparator(mixing in both kits mixing bottles; using reagents from both kits)....using the TF comparator it reads 60ppm.

This hurts my head....??????????
 
That is consistent with the results from the calibration solution, and again points to the TF comparator. This is the advantage of using the calibration solution, it shows us which of the view tubes is correct, which would be impossible to determine without the calibration solution.
 
I am thinking the tube defect attributes can only be related to volume(tube size and/or line placement) and darkness value of dot.

My tube is:

.2 mm wall thick
104.6 mm tall
118.75 mm outside dia at hard base
the 100 line is ~33mm from base
the 50 line is ~55mm from base
the 40 line is ~65mm from base
the 30 line is ~80mm from base
the 20 line is ~102.5mm from base

I am not sure how to measure the darkness value of the dot. I don't have a spectrophotometer and I cant get my camera to focus on a dot that small. And even if I could it would only be able to give me answer relative to another darkness value. I have no idea what the dot's value should be relative to.
 

Enjoying this content?

Support TFP with a donation.

Give Support
Here is reasonably good photos of empty, solution at 50%,40%,30% and at mid way between 30% and 20% gradients. This is another batch from today....same results as the several yesterday.. What do you read as the CYA ppmtests.jpg
 
Chem Geek,

You have sold me on the need adjust FC as a function of CYA levels....but my CYA is either just right or extremely high....!!!!

JasonLion's notion that if the 50% test solution was defective, he would have heard several complaints......not if I am the first to get this batch.....but I just noticed: there isn't any lot/batch/mfg date, etc to identify the source. That is a red flag to me, being anal about process control.
 
I started to investigate the effect of a 4degF change on test results and found your (Chem Geek) input on another forum....http://x.havuz.org/viewtopic.php?p=32211

No impact....I have ruled out my "reading" ability as the culprit of inaccurate calibration tests:

That leaves:
1. Reagent
2. Test Solution
3. Tube (volume or gradient)

Based on emails from Taylor, I am scratching test tube comparator.

That leaves test solution and/or reagent, neither having a lot,batch,mfg date or any other means to id source.....
 
The height of the markings from the bottom on the two view tubes should match exactly. If yours are different then one of the two view tubes is defective. You only listed one set of view tube marking heights. Do your two view tubes match, or are the marking heights different? And if different, which tube did you list the measurements of? Finally, were you measuring from the bottom of the physical tube, or the bottom of the area that gets filled with solution?

With the currently available information we can't prove which one is defective, but we can play the odds. The odds at the moment are tilted very strongly in one direction.

By the by, volume has nothing do with it. The important criteria are height of the solution being tested and visual contrast of the black dot.
 
JasonLion,

I must have confused you, I only have one large tube that I purchased from TF Kits. I used the solution that I mixed from the 50% test solution (purchased from TF Kits) and the R-0013 reagent (purchased from TF Kits) in my K2006 CYA test comparator.

The measurements are from the inside along the side of the tube. Not from the top of the dot, which I estimate is less than .2 mm above the flat white circle. I cant measure the height of the dot's mound, but it is well within my +-.5mm tolerance.
 
BTW, TF Kits has mailed me another tube (I expect to receive Thurs or Friday), but the measurement that Dave gave me from the outside bottom of the tube to the 100ppm gradient was 33mm, same as mine. Based on that one measurement, I not expecting that the new tube will solve the puzzle.

I am leaning towards reagent or test solution. I have ordered both test solution and reagent directly from Taylor (my assumption is that they are the "freshest" product, being earlier in the supply chain). And if I understand CYA, "freshness" shouldn't even be an issue.
 
If you have a K-2006, it includes a comparator block with two sides, one side of which doubles as a CYA view tube. The heights of the CYA markings on the K-2006 test block can be compared to the heights of the CYA markings on the TFTestKits view tube.

You also refer above to doing something that caused the calibration solution to read as 50 ppm.
I mixed in the TFTestkit large mixing bottle in the Taylor R2006 comparator and would get 50ppm ish every time
Click to expand...
I took that to mean that you were using the view tube integral to the K-2006 test block and getting different results from what you got using the view tube that came from TFTestKits. If I read correctly, the only difference was one time you used the K-2006 block as a CYA view tube and the other time you used the TF Test Kits view tube, and the results came out differently.

If I read that correctly, the only possible answer is that the view tube integral to the K-2006 block and the view tube from TFTestKits must be different in some way. The only two relevant ways they can be different are the height of the markings relative to the bottom of the solution and the visual contrast of their respective black dots. The block dot visual contrast is tricky to measure, but the vertical heights should be easy to compare.
 
JasonLion,

Your para 1-3 are spot on. (correct) And attach are the measurements of the TF Tube and the K2006 tube....all except 30 and 40 are within .5mm. It is much harder to mic the K2006 because I cant look through a gradient line..it is a lateral read. Plus my mic has a black probe and I am reading against a black k2006 background.....but I conclude both will yield the same column height of solution relative to the equivalent gradient, or so close as not to matter.

The K2006 yielded a consistent 50ppm and the K100 yielded a consistent 30ppm re-using the exact same mixed (50%Test + R0013 reagent) solution. BTW does again today, with today's calibration mix

I am an oil painter (no Monet) but I understand gray scale values. It appears and I underscore appears....that the K2006 is just a smidgen grayer, (but hard to tell because of size), but what is remarkable is how much more shinier the K100 is. It has an almost mirror finish and a translucent quality, where the K2006 has a much duller quality and no shine at allView attachment 31033.
 
JasonLion,

The K2006 black dot is flat (both in color and depth) the black dot in the K100 is like looking into an eye; it gives the illusion of much greater depth than the real depth of ~ .2-.3mm convex shape of the tube bottom.

The white circle of the K100 is at least 1/2 a value lighter and maybe a full value lighter(10 scale between black and white). Also the white circle of the K100 doesn't cover the bottom of the tube, unlike the white square does cover the entire base of the K2006 tube. You can get a sense on reflected light by the two pics....exact same camera set up and lighting conditions


View attachment 31039
 
This may end up as a Customer Service issue that, by forum rule, is not permitted on the forum. Let's see where it goes....

On 6/14/14, you ordered a Taylor K-2006

On 6/17/14 You ordered a TFTestkits CYA test

On 6/18/14 You ordered a R-7065 CYA Standard Solutions Reagent.......all three of these orders were placed with TFTestkits

Within this time frame, have you also ordered R-0013 and R-7065 directly from Taylor Technologies?

Please help me understand the goal. I am lost.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply