I'm trying to get the chlorine level in my pool to zero so I can acid clean to remove the iron stains, but it's taking a very long time. On March 27 the FC was 4.5 and I turned off the liquidator. This morning (10 days later) the FC is 2.0. My question is how much ascorbic acid would be consumed by the chlorine at 2.0 ppm? I only have 5 lbs of AA so I don't want to waste much, but I have to go out of town next week and would like to get started asap.