Thanks, The kasco surface aerator is a motor with 2 blade prop aimed up sitting in floating ring like this but unsure of the hp size. http://www.aquaticponds.com/Kasco-Marine...7cNrhoCUmTw_wcB

The fountain or cascade is maybe a foot above the top of water.

I have a good amount of duckweed on the pond bottom as well. Will the duckweed on bottom surface or is it dead?

I suppose using the aerator as a circulator could help by mounting a motor horizontal instead of vertical if nothing else if it produces enough wake it may put all the duckweed together to ease in skimming it with net.