Hi, I tested my water using the FAS-DPD test kit and my free chlorine reading was 4.2. I used the 25 ml sample which needed 21 drops of R-0871 before it turned colorless. I took the water into Leslie's to confirm my test results. Leslie's informed me that I had 1.5 for free chlorine. I believe they use the DPD method.
I don't know whether or not I messed up. Does the amount of R-0870 impact the amount of R-0871 needed to make the water colorless by that much? I would be interested to hear other people's experience / thoughts. Thanks.