Note about Aquathol K super granules. Applied to pondweed in summer (July) it is not fast acting, took about 2 weeks to have an effect. Of course the pond weed is very thick at the height of summer and probably much harder to kill. I used about 1 pound to clear 25 ft circle around my dock. Put another 4 pounds out to try and enlarge the circle a bit. I think I may have a small swimming hole though by mid August! Work you blasted Grass Carp!
