No chlorine + people 'goo' equals FC=0 *and* CC=0

Add 10 ppm chlorine to a pool with no 'goo', and you get FC=10. But add 10 ppm to a pool or spa full of 'goo' and you can get anything from FC=0 & CC= 0 to FC=0 & CC=10 to FC=5 & CC=5

Talking about people 'goo' . . . bugs many people, because they aren't comfortable the stuff that their body does, or that other people do.

Without getting into more detail, putting 2 people in a hot tub on 6 different occasions, and keeping the spa covered between is MORE than enough to account for your CC results.

You *can* chlorinate the CC out, but unless you are in a water restricted area, it's better to use it to water the flowers than to add to the pool. (Plants like people goo, more or less!)