Hi
An idea I use is to get a long plastic tube / stick. At one end, put about four screws in half way an inch apart at different levels up the pole / stick.( not in a line but around the pole) Place this in the pond along the side and turn the pole which in turn rotates the screws which catch the blanket weed. Because the weed is all joined, it accumulates on the pole. Remove the pole and cut off the weed exposing the screws again for more weed removal.