CC Test


Well-known member
Apr 21, 2020
Apex, NC
As you can see in my signature, I use the K-2006 kit. For testing FC and CC, I use the FAS-DPD test. I have a question about the CC test. It says after adding 5 drops of R-0003, if the sample turns pink, add R-0871 until it turns clear again. Every time I run this test, the sample turns the very slightest of pink. You can barely see the pink. One drop of R-0871 easily turns it clear. It seems to me that the CC is closer to 0 than to 0.5ppm. Should I be recording this as 0.5ppm as I have in the past? I have not been running the 25ml test but it wouldn't surprise me if I got a 0.2ppm result.


Gold Supporter
Bronze Supporter
Jun 11, 2018
Verona, MO
I don’t worry if it is .5 or zero. Maybe if testing in evening and cc should have burned off, but still essentially zero.


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
My opinion os that your CCs are zero. One drop of titrant is the limit of the test so it’s statistically insignificant if it’s one drop. That faint color you see can easily be coming from air oxidizing the DPD dye as it is sensitive to oxygen.

The answer is effectively 0. If you did the 25mL test, my bet is it would be one drop also. Again, that’s effectively 0.
Thread Status
Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.