Well, I think it started getting muddy after rains..around the time a small junkyard near us had all the cars taken away. I think they had some clay runoff from not planting any grass, but that was a couple years back. (Hes been in the logging business before too coincidentally)

There's also some minor things going on up that way in the area but I'm not really sure exactly where the stream runs. I'll have to try to track it on google earth again.

The stream gets little flow but is constant. It must flow about 3 miles from a spring, so it will pick up a little runoff. I think I can find a way to make sure nothing comes in by filtering it.

What if I dug a small area for the water to collect into a pipe to run into the pond? Using a screen to catch large stuff and then a filter of some kind surely that would catch anything right? Anyone see or have a set-up like that?

I think if I can clear up the water and get a little more of the excess muck out of the pond, then the pond should be okay for a while. It just occured to me until Rainman touched on the bacteria needing sunlight...the muddy water must be keeping anything from breaking down.