CYA test difficulties

[KerryR]

Hi all,

I'm new to the forum. This is my first post.

I just got my TF-100 test kit. As you probably know, the test kit comes with a sample of 50ppm CYA water, to help the new tester understand the test.

I followed the directions for the test as printed. Because the provided sample is known to have 50ppm CYA, the dot should be obscured around 50 on the test vial. At this level, the dot is still clearly visible. It doesn't disappear until about the 40 mark on the vial. I followed the directions accurately, twice, with the same results-- the dot's not even close to vanishing at 50, always around 38-40. I've poured the fluid out and repeated the fill many times, with consistent results of 38 (a little higher than the 40 mark). But not the 50 it SHOULD be.

I'm doing the test outside, observing the test tube with my back to the sun, as suggested in the video (though in the video, the tester is facing the sun).

I watched the TF CYA video, and referred to the test pics on Taylors website. I'm not even close.

Any thoughts?

This is the first test I'll do when I think I have it working, so I don't have any other data, yet.

Any help would be great.

Thanks,
Kerry

 

[duraleigh]

Welcome to the forum. The CYA test is very subjective. When you are new, it is VERY difficult to get it exactly right.

So, take the R-0013 and 50 standard solution and put them in the view tube in equal quantities.

put what it lopoks like in your Minds eye. Now, mix your pool water and the R-0013 reagent and put it into the view tube until it matches the obscurity level you have remembered fro the standard solution. The result will be the CYA that is in your pool.

Don't overthink this. In perfect conditions, you will only get + or - 10 ppm, anyway, but this method is a "backdoor" way of arriving as close as you can get it.

If you become obsessed with obtaining more accuracy, you might as well order some more 50 ppm sample and R-0013.....I think you can do about 3 tests with the 50 ppm standard solution but I can't remember for sure.

 

[KerryR]

Oh, OK.

Thanks for your help. Appreciated.

Cheers,
Kerry

 

[pooldv]

Right, that solution is an eyeball calibration tool. That is what 50ppm looks like. Now, you just need to train your eye to look for that.