Duckweed taking hold in my pond

I hear sonar will kill it.

Good luck that stuff is a beast

Sprayed AquaKleen/Navigate last friday and there is no more duck weed in the pond. and its a 2 acre pond

I heard there is a corn meal that will back it off if we are talking the same type of weed. Real small light green? Looks like a carpet but thin? Horticultural corn meal is used in various form for things like pond weeds, pre emergent on lawns, brown spot in San Augustine grass. I've tried it on the latter and it worked great.

I had a cousin that took a fine dip net and dipped it out of our .5 acre pond