Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Losing the battle with Duckweed

I'd use Clipper (flumioxazin) if I was you. 1.75 acres with the top acre foot of water is 1.75 acre feet. Apply Clipper at 1 lb per acre foot (200 ppb). Might have to reapply in a couple of months to pick up the stragglers that were caught up in the grass or washed in after
the initial treatment.