I am having a problem when I see CYA readings of 150 ppm from some water analyses lately. The test I use can only go up to 100 ppm. These readings need to be qualified more accurately, granted that is a very subjective test.

The moment 150 ppm CYA is mentioned, the consensus seems to want to drain the pool. WHOOOOOOA. Draining water is a big decision and should not be taken lightly.

Testing CYA levels IHMO is not taken seriously enough, because it is very subjective. IMHO it is the most important test to be done, as it appears not affected by any other chemicals. As such I would like to see a standard set up in this forum for testing CYA levels. For what it is worth, this is what I do.

1. Purchase the large sampling tube with the plunger that has the black dot on it.

2. Buy a gallon of Taylor R0013 reagent, and small sampling bottle to put some of the reagent in. I keep this in the bathroom under the sink, where there isno light 95% of the time.

3. Make sure the sampling tube is scrupulously clean. Use an old toothbrush if necessary, or straight bleach.

4. Add the pool sample to the A mark, and R0013 reagent from the small bottle to the B mark.

5. Wait at least 1 minute before taking the reading.

6. This is important. Face a North facing window, holding the sampling tube by the base so as not to interfere with any light from the window. If you face the sun, there might be extra light coming in to affect the reading.

7. Slowly raise the plunger, and as soon as you see the black dot, that is your measurement. If you are not sure of the measurement, or don't believe it, have someone else take the reading again. If you agree, then that is the reading to use.

Hope this helps.

Pat