Not an expert on this but I will comment.

In my area we have lake property owners on our public lakes that spray for weeds every year about the time the bluegills go on the beds. Once they spray you might as well hang up the pole, as the fish scatter and don't seem to come back. I don't know what they are spraying, but the funny thing is the weeds come back about a month later.

What a stupid waste of money.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.