We are based in Georgia, have a 1 acre pond, use a three head aerator and treat the water with bacteria (Bait-klear) and Cutrine. The water quality appears ok, and weeds are controlled (courtesy of grass carp).
We have a white-ish film that appears in one shallow area of the pond (picture attached). When we have a rain shower the film disappears however it re-appears the next day. We don't think this is due to dust and it happens at times of year when there is little pollen (e.g. mid-Summer).
My pond goes through similar phases. Some are mild given some rain, but without the rain it can get pretty scummy on the surface. This Filed Guide will help you identify what you have. I'm thinking Protozoan Scum and/or Diatom Blooms...
