Dave, I was wondering if you think it would be a good idea to use flock after a stain treatment, when the stain is all off and there is enough sequestering agent in the water. I was thinking that if you use flock, then shut down the pump overnight, then vacuum to waste, it would then get rid of some of the metal that was in the water - or is the metal that combined with the sequestering agent just going to stay suspended in the water? I really don't know about real chemistry, so please excuse me if this is a silly question!