To answer the last question, yes I've done jar tests with soil, haven't tried it with just pond water. With my soil the water never clears.
I probably should get the pH checked before trying any alum/quicklime treatment, as the water that filled it was likely on the acidic side here in the Piney Woods, and I already added about 1/2 ton of aglime. There are no streams or ponds above to get bullheads or carp from, just grass waterway, but I stocked 100 4-6"CC and 50 6-8"CC which I assume will stir things up in the future.
It's not real muddy at present, you can see down 18" or so, an opaque gray-brown color.
