I found a better view on another program, and I think I found the pond but couldn't copy it. I'll trust that you are between 1/2 and 1 acre like you said, and that the pond is not a long skinny geometry.
Therefore I think you will get along fine with either a VERTEX AIR 1 or a KEETON KR2
Use Aquatron and add a 1/2-pound water-soluble-packet every week or two during the fertile season until it is gone.
Or you can use Waste & Sludge Remover on a regular basis similar to Aquatron.
I would start out with the C & C/C-Flo method if you get this moving really soon. Then next spring if you want to push it a little, you can add more of the same or get a 10# pail of Aquatron.
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