Is it accurate to do an FC test using 1 scoop and 5ML water sample and counting each drop of R087 as 1 ppm FC? My FC is at about 13 and it seemed to work well. Thoughts?
I use one rounded scoop of powder but have never tried the 5 ml of water. Have you done a back to back test with the 10ml of water and 5 ml to see if they "match"? I think the 10ml uses little enough regents I do not worry about it.
Keep in mind, any time you use less volume, the precision of the test is decreased.
From Pool School - FAS-DPD Chlorine Test The precision of the measurement is plus or minus one drop when up to 10 drops of titrant are used, or plus or minus 10% of the final reading, when more than 10 drops of titrant are used.
Keep in mind, any time you use less volume, the precision of the test is decreased.
From Pool School - FAS-DPD Chlorine Test The precision of the measurement is plus or minus one drop when up to 10 drops of titrant are used, or plus or minus 10% of the final reading, when more than 10 drops of titrant are used.
Right, so to illustrate, if you are using the 10 ml sample your error rate will be +/- 0.5 ppm up to 5 FC, 1 ppm at 10 FC, and 2 ppm at 20 FC. If you are using the 5 ml sample then your margin of error is double that. So a reading of 13 means your FC is between 10.5 and 15.5 (rounded).
Right, so to illustrate, if you are using the 10 ml sample your error rate will be +/- 0.5 ppm up to 5 FC, 1 ppm at 10 FC, and 2 ppm at 20 FC. If you are using the 5 ml sample then your margin of error is double that. So a reading of 13 means your FC is between 10.5 and 15.5 (rounded).
Okay thanks for the input. I have been using 1 round scoop of powder and 10ML water sample, but I tried it with 5Ml and got the same results, so that is why I posted the question. Seeing that the margin of error increases I will stick with the 10ML water sample. Thank you for all the responses.
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