I'm waiting for the water temperature to get below 60 before closing but getting all the chemicals ready. It's a pretty big pool (53K gallons) so I've picked up 3 quarts of Polyquat 60 and 15 gallons of 12.5% liquid chlorine. Because it's an SWG pool, I keep my CYA between 70 and 80, so according to Pool School my Shock FC level is between 28 and 31. I want to make sure that I've poured in enough chlorine to reach Shock FC level, but using the TF-100 kit, that means that I have to count up to 62 drops.
I'm bound to lose count by the time I get to 40 drops, so here's my question: Does it make sense to reduce the amount of water in the FC test to 5 ml instead of 10 ml, and count each drop as 1 ppm instead of .5 ppm? I know accuracy of the FC measurement will be reduced but is it enough to matter given that the pool is being closed and the FC level is going to need to drop anyway for the Polyquat 60 to go in?