CYA Standard R-7065

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So I tried again today and I still get 70 ppm with the sun at my back, waist level and if I turn into the sun and add more light, 60 ppm...with the R-7065.

My own water comes back around 35 ish...which is inline with what I expect from the amount I added although I expected it to be more like 40 ppm.

Since it is Saturday, I ran a full suite of tests:

FC 5
CC 0
pH 7.5 - 7.8
TA 90
CH 220
CYA 35

Days Since Water Filled Due to New Pebble Sheen Refinish 37
 
Just for grins, I ordered up a Taylor K-2006 kit. I wanted to see if I could get 50 ppm for the R-7065 solution using THAT kit. Well guess what? I did!!

Something perhaps subtle that I noticed in the instructions for the CYA test in the Taylor kit says to mix the solution for 30 seconds.

I just checked the instructions for the TF-100 kit and it says to 'mix, wait 30 seconds, shake once more.'

I think I'm missing the 30 seconds of mixing because when I did that, I was able to NAIL the 50 ppm mark in both the Taylor kit and in the TF-100 kit.

Perhaps this is a small case to have the instructions for the TF-100 CYA test adjusted a tiny bit?? :)
 
The proper instruction is to mix for 30 seconds where the mixing is a slow back and forth of the vial or bottle. The instructions should not say to mix and wait 30 seconds and then mix again. One is supposed to continue to mix gently for 30 seconds. This ensures that the chemicals completely disperse and mix with each other to form the cloudy precipitate. The Extended Test Kit Instructions say to "Cap and then shake the mixing bottle for 30 seconds." I'd word that more as "gently mix tilting the bottle back and forth" rather than "shake" since you don't want to introduce a lot of bubbles into the liquid.

What is strange is that by your not mixing the entire time you got a higher CYA reading. I would have expected not mixing well to have a lower CYA reading since the water would be more clear. How is it that your not mixing the entire time is having the water be more cloudy? Do you see a white percipitate settling onto the black dot to obscure it?
 
Ah, I see that for the extended but the label in my TF-100 kit and at TFtestkits don't actually say to mix for 30 s. I think some correction is in order to make things consistent.

Well, I did shake it but certainly not for 30 s. Maybe for 5 s and then I let it sit for 30+ s and the a couple more shakes and then did my readings. Sometimes I'd pour it back into the bottle, reshake, and try again.

I don't recall any percipitate settling and I agree with you...it is strange. I'll experiment some more tonight and see if I can figure just what the heck I'm doing!
 
I tested my monthly CYA level today, trying the R-7065 test solution again after my 1st test about 4 weeks ago.

Using the Taylor Test Tube:

I tested with pool water and got consistent results of 45-50 (4-5 times, pouring solution back into Tube and re-testing).

I tested with the R-7065 solution 4-5 times. This time, I got the same results as with the pool water.

I guess I needed to get acclimated using the R-7065 solution a 2nd time after my 1st try with it last month.

The test result was what I wanted to see, a drop of about 10 from the last test. It's tracking about the same as last summer with the level decreasing ~10 per month between June and early November.
 
you perhaps a strange question, but wanted to get input. Lots of talk here about adjusting the "tester" to get the right results. I too ordered 7065 and am getting consistent 30 results. Is it possible to relabel the tube to adjust the measurement equipment to match my notion of what test results should be? I calibrate lots of other test equip - why not this? If I have a good "standard," cant I adjust the measurement standards to meet what I observe? It's just a log scale on the tube, right?
 
Yes - Yes - I get that but my point is that I have jumped through hoops and stood on my head and juggled live chickens and when I test with 7065 std, I always read 30. Is there a reason that I wouldn't recalibrate the tube to match my results?
 
No, but you have to remember that you did it, in case some one wonders later...

Since you are reading low, which means too much light, just find a place with less light or find a way to shade the test vial.

Plus, since it's log scale the divisions at 30 aren't the same as those at 50. You know that, but I think you are limiting your resolution by recalibrating the scale. Of course, for me, this is all thought experiment, so I could be seeing an issue that isn't really there.
 
shawnra said:
Yes - Yes - I get that but my point is that I have jumped through hoops and stood on my head and juggled live chickens and when I test with 7065 std, I always read 30. Is there a reason that I wouldn't recalibrate the tube to match my results?
Click to expand...

I feel your pain. I too could never get the standard to read 50ppm, even was sent a new bottle. I've spoken to Dave over the phone and he assures me I am doing the test correctly. I gave up back in July and trusted my eyes with the standard, swg is keeping my chlorine steady and water has been crystal clear all summer. I just decided to not overthink it.
 

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Thread isn't that old.
Decided to test inside.
Since I have the standard and everything is the same then it is valid.
Lots of rain past two weeks which is good.
TA dropped from 110 to 100
pH 7.4

CYA TESTING:
Dining room light on.
Tube on white paper towel.
Head hovering, glancing at dot, about 8" above.

I feel 50 on the dot, pun intended. Was 60 on 8/6.
Wife sees 45 but "it's hard when they aren't side by side."
correct she is.
Maintaining FC 5-7. Drops to 3 for less than 24 hours with no worries.
Have an awesome week. Time for our staycation.
 
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