Water Testing Instructions on One Page

[linen]

It has come to the moderators attention that the following section of the "Water Testing Instructions of One Page" instructing how to do a dilution test when cya is above 90 ppm, is incorrect.

Here are the original incorrect instructions (cut on 6/6/12):

For CYA >90ppm:
Mix sample as above then cut 50/50 with filtered tap water; do the black-dot test, and double the reading.
OR, mix a smaller sample to begin with:
a) Measure 4ml R-0013 into the mixing bottle.
b) Measure 4ml pool water into the mixing bottle.
c) Measure 8ml tap water into the mixing bottle.
d) Continue from step 3 above.

The correct method for a cya dilution when cya is above 90 ppm is from the extended test kit directions. I have modified it slightly to fit the format on this thread's first post:

For CYA > 90ppm, repeat the test adjusting the procedure as follows:
a) Fill the mixing bottle to the lower mark with pool water.
b) Continue filling the mixing bottle to the upper mark with tap water.
c) Shake briefly to mix.
d) Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
e) Continue the test normally from step 3, but multiply the final result by two.

Since PaulR has not been on the forum for awhile, I have taken the liberty of editing his post.

Note: the attached pdf does not reflect this correction yet.

 

[lka674]

I have a question about the CYA test. It's a very subjective visual test, and my eyes aren't all that great to begin with, so... what exactly does "until the black dot just disappears" mean? When I do the test, there are usually bubbles that form each time I add a few drops of the solution, and I figure I have to wait for them to clear first to see the dot since they obscure my view. And also, sometimes the immediate result after adding a few drops is that the black dot disappears for a second or two, but then reappears. So, do I count that as the point where it "just disappears," or since it reappeared within seconds, do I keep going until it stays completely invisible?

I knew joining this forum the other day was the best thing I've done since we built our pool!
THIS was my exact thoughts on the CYA test...perfectly described!

Thank you for asking and to all who gave the answer! One more issue I can mark off my list!

 

[astronaut888]

You want to add as little liquid as possible and still have the black dot remain invisible after several seconds.

http://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=44

In the above link from Taylor - I certainly see the black dot pretty readily in the photo that they post as the "end" of the test - I don't think that it is very subjective that the dot is still visible in their example

 

[JasonLion]

In the Taylor photo at the end of the test you are seeing the round bottom of the view tube, not the black dot. Compare the diameter of the dots and you will see that the "dot" in the final photo is larger.

 

[astronaut888]

In the Taylor photo at the end of the test you are seeing the round bottom of the view tube, not the black dot. Compare the diameter of the dots and you will see that the "dot" in the final photo is larger.

Yeah- i guess i see that - just having a little difficulty getting the hang of this