CYA test taylor k2006c

[azanclay]

Just got my test kit yesterday. First time pool owner here. For the cya test I am not clear with the instructions it says to add the mixed solution of cya reagent and pool water into the test vial until black dot “just” disappears. Does this mean add the mixed solution until the black dot ‘completely’ disappear? I took a picture of my black dot today. So this is at concentration of 30 ppm (last line on the vial) and i could still see the black dot but very blurry.

 

[mknauss]

Welcome to the forum!
The CYA test is the most difficult to master. I do the following, see if it works for you.
Once you have your solution ready, back to the sun, etc. Fill the vial to a line, say 80, lower the vial to your waist level and glance for the dot, you see it, add solution to the 70 line, glance, see it, repeat until you no longer see it with a glance. Then use the CYA value one step above the line you read. So if you stopped at 50, use 60 ppm CYA.

The vial is in logarithmic scale. So it is not viable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....
I suggest you read ABC's of Pool Water Chemistry.

 

[Randrx2]

That dot is pretty disappeared. At least I would call it disappeared.

That picture looks like it is in the shade. I have noticed that if you hold vial with your back to sun and get to a point where the dot disappears, when you bring the vial into the shade, the dot re-appears. Something to do with the refraction of the light in the shade.