QA, sounds to me that you have solved one problem since you no longer see light plumes of muddy water. My Kasco diffusers are about 12" tall so by me setting them on a 21"table stand it puts me in or around the same height off bottom that you describe. I no longer get those lightly colored muddy plumes. I sent a water sample to Bill Cody where he analyzed my water. I would suggest you ask him for some help in analyzing yours. Any information he offers will help you to determine what might be going on with your ponds water.
