One question first: Does you well water you used to fill the pond have iron in it? The reason I ask is when I first fill my ponds with my well water, they start out kind of brownish/green and as the iron settles it becomes a murky green and then finally crystal clear. Iron in low concentrations appears a kind of army green. Not saying that is it, but it could be.

Why not put some in a clear jar and see if it settles and how long it takes? Then come back with the results and we can take if from there.

What kind of alkalinity and PH do you have? Low PH and alkalinity you could treat with gypsum to clear the water, higher PH and alkalinity to buffer PH changes you could use Alum.

Could your waterfall be stirring up your bottom or prevent settling? Furthermore it has been my experience that all new ponds are somewhat murky until some diatoms, phytoplankton, zooplankton, and macrophytes become established.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.