Aquathol K is effective for treating American Pondweed - the weed with the narrow pointed leaves that float on the surface in shallow areas. However, the product is too expensive to treat ponds larger than 1/2 acre. As for weed moss - Cutrine Plus works pretty well on Filamentous Algae, but not sure about Chara (Muskgrass). I've had cattails in profusion in a couple of ponds, but have never attempted to treat it. The cattails slowly disappeared after a few years. Maybe the Aquathol K that was used to treat the pondweed also had an effect on the cattails.