Good job! Keep going with the high chlorine levels until the pool is clear AND until you can go from sundown one night to sunup the next morning without losing more than 1 ppm of chlorine, AND your CC = 0. The residue that you're seeing is probably just dead algae, and can either be brushed up so the filter can get it, or when it's over you can just vac them to waste.

Keep up the good work!