We have a Pentair Challenger 5 Hp pump and two 36" sand filters. I have so far added 4 times 11 jugs (96 fl oz) 6% bleach and 1 time 14 jugs (96 fl oz) of bleach. I waited a day or two in between putting in the bleach. I also used approx. 2 lbs of Super Chlo Calcium Hypochlorite (67%) twice when I had no bleach at hand. Brushed a lot and fished out a lot and backwashed 6 or 7 times. Put in approx. 25 lbs of soda bicarb to raise the TA and one jug muratic acid to get the pH from purple down to red.