Were all of the stains gone first, and coming back now - or were they never lifted off in the first place. If the stains just came back, drop your ph back to 7 and add more sequestering agent. If the stains never came off in the first place, add more ascorbic acid and let the pump circulate for a while. Your water shouldn't get very cloudy again, maybe just a little. You don't need to take you chlorine down again, but watch it because the ascorbic acid will use up the chlorine fast. I am surprised about the cya, did you lose any water?