Well, I don't think I would have believed this if I hadn't experienced it. I have been adding chlorine following Chem Geeks experience ( Thanks - wouldn't have had the courage to do it otherwise!). Gave it a really large dose yesterday morning and then retested and added bleach every 1-2 hours all day yesterday about 1.5 - 3 gallons at a time. Now, some nearly 35 gallons of bleach later, I am still not there yet. I went ahead and added some stabilized chlorine (I was out of bleach) this morning because my FC was down to 0.8 and my CC was still 1.2 and I was afraid to go off to church for a couple of hours and lose the last of my FC. That did get my FC up to about 15, but it is already back down to 2.5 with CC now at 0.8. Off to get more bleach and I will continue today as yesterday. I'm sure glad its a long weekend and I have time to deal with this! I don't know what the nasty thing is that's in my water - but I sure hope I can finish killing it today!! The amazing thing is the water is crystal clear!