So last 2 years I have been trying out how to maintain a pond. Playing around with sealing the pond naturally, controlling Green Sunfish, etc. Last year I let it dry up, cleaned it out, and now I have a really clear water pond, that holds water like a champ!

New problem, I have a submerged weed (most likely generic Pond weed) that is touching the surface or are just below in most areas.. There are several animals that access this pond as water, so there is plenty of fertilizer, and I just released hatchery fish into the pond. I also have some geese and few duck that I hope will better control the weeds, but I really believe I need a herbicide. I dont want to kill my fish, harm the live stock, or kill off too much plants that kills my fish.

I am leaning towards Sonar, but I cant for the life of me find any place to buy it online, and I am worried if I find a "deal", it will be diluted, or not correct chemical.

So I need some help in choosing the best chemical (slow is most likely the best at this point) and where to get it.