thats normal, if you cant stand it consider an aerator that really moves the surface of the water. moving the water will make it look better. check your visibility, if its 12-18 inches consider backing off some on the fertilizer. add 1/2 as much an see what happens, you can always add more. try to keep visibility around 18-24, you will like the appearance of the pond much better and fish seem to bite a bit better. I think because they can see better