Guess I missed this thread, but replied more in depth on Bill's new thread.
In short, the follow-up photos appear to be what many folks call American pond weed, but it is more widely known as "long-leaf pond weed", or
Potamogeton nodosus among aqua-nerds.
I agree with leaving it alone, or modestly managing it if it becomes too unruly. It's generally well-behaved; being regulated by habitat depth, except perhaps in ponds with significantly fluctuating water-levels.
Possibly of greater concern is when a more invasive weed species appears and begins to out-compete the existing long-leaf pond weed. That's when it may become very difficult to target one species without negatively impacting the other; so avoid that scenario if at all possible.
