HI-
Well, I have had my tub for a month so I cleaned the filter that is always on and rotated it with the others, then I decided to do a chlorine shock. (MPS for 3 weeks, chlorine on the 4th).
My tub looked a little like a bubble bath with foam flying around in the wind. Not all over, just in the turbulent places. Later that day we used it, and it didn't really foam at all. Does this happen each time you chlorine shock, or maybe I left a little filter cleaner on the filter?