Usually means you have suspended particulate matter. It can be algae or clay. The good thing is it settles out, so probably not an ionic type bond holding the matter in suspension. More likely something in the pond is stirring up clay, or you have surface water agitating the clay as it flows into your pond.

Is your pond full yet? I would bet you need more ground cover to keep the clay from agitating. It could be on your immediate watershed or from offsite as water flows to the pond.

Is there any green or olive color to your water? Algae bloom will reduce clarity and is normally a good thing. If you hang a white coffee cup in the water column, how deep does it go before it disappears? This is a redneck Secchi disc test.