How to Read the CYA Black Dot test

[les_garten]

Pinch a Penny tested my water today. Lots of differences in how my results come out and how theirs come out.

But the test I'd like to ask about is the CYA black dot test. I read it around 40 and they read it at 90. When they tested, I asked to look at the test. I did not discuss with them because that would most likely be useless I have determined in the past.

Here's how I read the dot test. If I can make out the dot, I call it, it's very milky, but if I can see the dot as a dot, I read it. I think they read it as a "clear" dot.

How do you folks read the dot?

 

[mknauss]

When you do the CYA test, try this next time.

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 a non linear scale. So it is not reasonable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

 

[jknapp86]

When you do the CYA test, try this next time.

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 a non linear scale. So it is not reasonable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

Ooo so when I stop seeing it at like let’s say 30 my CYA isn’t in-fact 30 but the next highest number/line down? If so I’ve been reading it wrong all along.

 

[les_garten]

When you do the CYA test, try this next time.

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 a non linear scale. So it is not reasonable to interpolate between the lines. Just use the whole numbers, such as 50, 40, 30, ....

I've got this test kit. It has an A and a B on the back of the reading gadget

I just keep raising and lowering it to catch the dot the moment it appears.

 

[mknauss]

That is fine. Just remember to round up to the next whole decade number.