My pond was really dirty last year, we had 11-1/2" of rain in the month June which is more than a third of our average annual rainfall here. This included two separate 4" downpours that came down in a few hours, it was the wettest June on record here.

I kind of like milfoil for fish habitat but it is pain to fish and looks bad in late July and August.

If you decide to try pond dye at ice out go conservative and leave at least 20-24" of visibility.