Ron,
You're obviously willing to put forth a lot of effort as indicated by your willingness to manually remove the weeds. You have learned, though, that the plants have the ability to spread through fragmentation. Another route that can be taken (non-chemical) is to shade-out the plants. You are probably aware of the dyes that are available, but I'm talking about using black plastic sheets to cover the weed beds. I've never done it, but I have seen photos of this method being used with successful results. You have an ideal pond in that it is fairly small and the weeds are mostly restricted to the shoreline areas. Just a thought.
