This is the worst year in 30 years of pool ownership for us. I cannot even count how many times that my pool has been slammed this summer, blue and then turns green again. I always use the chart showing the FC level for my acid level and slam the pool accordingly. I usually add a little extra and maintain that level overnight. About a week or so later I am starting to get green again even though I have chlorine in the pool. I use the pool store a lot for test but also have the Taylor 2006 test kit (new this year). I maintain my water perfectly except my PH creeps up at times because I use a lot of liquid chlorine which raises my PH. Right now I am also using the 53% cal-hypo because I am tired of dealing with the huge volume of chlorine this season. We are getting ready to go on vacation for 1 week and am trying to get it in line before and then drop in some tabs while we are gone. My acid is currently at 43 ppm. I have my PH back down to 7.7. Right now my FC is around 20 ppm (which is high). I know that the weather has been weird this year but this is crazy!