I add the 5 drops to test for FC, as per the instructions. I wait the 2 to 3 seconds and look at the reading. For the CC reading it states that you should just wait another minute or 2 with same water that I just tested the FC with. Oh, now I see that it's states that a desirable FC reading is 2.0. Then it states "a difference of more than 0.2 ppm between free chlorine and combined chlorine level indicates a need for super chlorination." I'm not even sure how I'd be able to tell if there is a 0.2 difference. Do you think they meant 2.0?