I have patches of brown floating scum. Dam was built in December 2004 and is filled by rain water. It was about 1.5 to 2 acres during the biggest rain fall and now is about 1/2 acre. Fish seem to be doing fine. Bass, catfish, bluegill and fatheads. Water has been leaking since the beginning but has slowed a lot. It was very muddy but has now cleared to about a foot visible. I have my well water running into it for this year assuming it will seal better as the pond gets older. None of the cattle ponds in the area have this scum. It looks really bad and increases daily. I have never done any fertilization or added anything except some fish food pellets and the well water. Can take pic.s and email if someone needs to see it. Any ideas?