Pond Boss Forums INTRO Questions & Observations White Film

I have a white to tan colored film on the water that has shown up periodically throughout this summer. I think I know what it is but I am not sure how to test for it. It seems that my neighbors (whom called the county, DNR, and Township when I was digging my pond with a permit!, and caused me all sorts of problems) are backwashing their pool onto my property about 50ft from the shore of the pond. this area is wooded and I can't see it from my house. Does that "diametasious earth" or whatever its called that is used in pool filters float? and does it come out in large quantities during a backwash? If not that cause does anybody else have any ideas what it might be? It is definetly white in color and not yellow or green.

What you are probably seeing is a natural sulfur reaction that occurs naturally in ponds. It is usually not harmful and not of concern. It happens in most cases where an outfall occurs.