I added citric acid to remove some rust stains and it worked great. I had brough my chlorine level up to 25 before hand knowing that it was going to drop and I did not want it going to zero like the last time I did this. Its been about 4 days now since I added it, the pH is back up to normal (I added some baking soda yesterday to get it back in range), but my chlorine is being consumed quite rapidly.
I shocked over the weekend to be sure. Sunday night I passed the overnight FC test. FC was 33.5 at night and 33.0 in the morning. That afternoon it was down to 25. Of course, I checked CYA and it is at 70 which I expected because I had just brought it up to there from 50 a week before.
So at this point I still going to assume the worst and keep shocking, but just curious how quickly will the citric acid deplete the chlorine? I would think as soon as it got mixed into the water, but ?????