That was quite a transformation. What do you think is contributing to the infestation in the first place? Runoff? How can that be prevented from happening?
I believe it was a couple of things...
1) I believe ducks were the reason for it being there
2) The pond had the perfect environment for it to cultivate such as being nutrient rich, no aeration, and being calm waters esp since the drain pipe was clogged
I am hoping to prevent it from happening again by clearing as many trees surrounding the pond that I can, as well as keeping that drain pipe free.
These are just my guesses so I could be wrong in my assessment.