We had 2 of my brothers and their kids over to swim for for most of the afternoon. I tested the chlorine with my K2005 kit a few minutes after the swimming was done and was at 3-6 FC, and while the test is a bit subjective since it's a color match, 0 CC. Did I test too soon? With chlorine at that level, is shocking or boosting tonight necessary? I didn't see anything in Pool School. I'd like to do something a little more scientific than my usual method of just dumping chlorine into the pool.