Trace CC

[KurtV]

I think it might be your testing procedure. Make sure you're adding enough drops of the R-0871 reagent. Per Taylor's website, "When you think you’ve reached the endpoint, add one more drop of titrant to be certain the color change is permanent. If the color remains unchanged, do not count this last drop." I've found that the Taylor FAS-DPD test will often incorrectly show 0.2 or 0.5 ppm (depending on the sample size) combined chlorine unless you follow that procedure

[azimmer1]

I will give that a try, but my sample is crystal clear before I add the potassium iodine.