So as per the chart, according to my CYA I have to maintain a FC level of 8. I have been doing that all year by adding 1 gallon of bleach a day and I have not had a problem at all. My water looks like diamonds when the sun shines on it. But I was wondering, can I let the chlorine drift to down to the lower number of say 5 or should I kick it over 8 (to say around 11 where 1 gallon should get me) and let it drift down to 8?