In almost every picture I see of pool construction, whether it is shotcrete or gunite being shot, I see the walls shot first. The workers are standing on the rebar in the pool floor, and there is always some concrete running down the wall, under the rebar & onto the floor. It is still there when the floor is shot. They just blast the shotcrete floor right on top of it. Is this the "rebound" I always hear about? Should it not be present? If it's so important, why aren't floors shot first so that whatever slides off the walls can just be scraped off? If the walls are shot first (like most builders seem to do), how much of this "run down" should I ask that they pick out from in between rebar & remove?