"someone" wrote ((big snip))

I found some celery-like plant in the stream on our local golf
course and brought a bit back, and it has cleared all the water, this
plant eats everything and keeps the water clear. If you want some, post
here with your munged email and I will send you some. It becomes a bit
rampant but does no harm, you can just yank it out.

Water Cress does the same thing and is excellent on the compost heap if it
becomes too rampant. Just buy some at the supermarket and throw it in, it
will soon grow roots and can be planted as a marginal. Just one thing, don't
use it from your pond for eating as you may end up with liver flukes.

--
Regards
Bob Hobden
W.of London. UK