Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants tilapia or sonar for watermill

I have been reading this forum for over a month and subscribed to your wonderfull magazine I am a new pond owner and love it! I have a 3/4 ac pond in the back of the house. I love to sit and watch the fish jump. I have a watermill problem probly brought in by the geese family and their 2 babies. I put in 15# of tilapia and planing on geting 20 more #. Will they get rid of the watermill? I was told they eat it, or should I get Sonar? Its so expensive. Is White Cap the same thing and is it a generic for Sonar ??? pleez let me know, the watermill ruining my veiw. thx p.s how do you get the bass to say I subscribe ???