My 1 acre pond was full of Eurasian milfoil and I found pulling it was futile. The research I did said that Eurasian milfoil wasn't a preferred plant for grass carp but I did put in 6 GC the first year and noticed some spots of Eurasian milfoil were starting to thin out. I put in 12 more the second year and in four years the milfoil was gone. Getting a balance of GC is the trick for me since I want some vegetation. I had a winter fish kill two years and so I am starting from scratch. I have Curly Pond Weed starting to get out of control so I have 6 GC coming in three weeks then I will see how things look this fall and next spring and decide if I need to add more. Before my GC died some had grown to three feet in 12 years.