Bill at the PBF get together at my place Bob Lusk ID'd it and called it Bushy Pondweed, which if I recall what he said correctly is one of the Potomogeton species as you said. Here is a picture he took as the group was around looking at it and discussing it.
We looked at a couple different bunches and Bob explained the difference in that one had a covering of FA and was not doing very good and the other was healthy. He explained how the FA and Bushy pond weed were competing for the nutrients in the pond and if I remove one the other would likely flourish and might become a problem.
So I decided leave it in to compete with the FA. It looks like decent cover for tiny fish. He said if it became a problem it would not get into very deep water and I could spot treat it along the bank to gain fishing access.
