On 14 Aug, 00:07, Galen Hekhuis wrote:
Wouldn't I risk their escape? The overflow from the pond runs right
into the Suwannee River.

In that case, what worked in my (much, much smaller pond) was to
overflow the pond so all the duck weed merrily ran out of the pond.
However it was much easier for me to arrange than it looks like it'll
be for you. I just sent the rainfall from the roof into the pond for
few months and all the duck weed went.

Matt