Testing CYA with R-7065 Standard Solution

[440dodge440]

I saw a post on here about helping to verify my CYA test by substituting R-7065 for the pool water, in which case I should read CYA of 50. So I ordered some R-7065 today, and I assume the procedure is the same with the exception of substituting the standard solution for the pool water. The CYA instructions are to mix, wait at least 30 seconds, then see when the black dot disappears. My questions is, what if I wait 2 minutes, or 4 minutes, does that matter? The reason I ask is that I may need to put the tube under different light, over a different ground color, or pour the solution back and forth between the mixing container and the CYA tube until I'm confident of the conditions that I'm reading the CYA of 50, and then use these conditions for the pool water test.

 

[jblizzle]

You should complete all your readings within a few minutes. The sample may change if you wait too long. I would think within 5 minutes would be safe.

 

[duraleigh]

while there is no known interference over time with that test, there is a limit on others. It is just good practice to get to your endpoint of any test and be done with it. There should be no rush but there is not time for lunch

 

[440dodge440]

Thanks. I think 5 minutes would be plenty. I just need a little time beyond the 30 seconds, and I didn't know if it continued to cloud and become invalid in a short time.