"Stephen M. Henning" wrote in message
news
I have a 20,000 gallon pond (17'x47'x2'-4') with just minnows, no Koi.
I put my filter plants directly in the pond rather than in a special
veggie filter. My pond is spring fed, so I need fairly aggressive
filter plants. The pond has stone wall sides (old swimming pool) but I
have greenhouse benches under the water around the outside so I can use
marginals or under water plants. My biggest problem is string algae.
It even grows on the end of the spring pipes, so the spring water has a
fair amount of nutrients in it. What are my best choices? Zone 6.

The best filter plants are those with a dense root system. There are
marginals that work very well like Water Iris, and Water Celery, and
floaters such as Water Hyacinth and Water Lettuce. The floaters usually
spread voraciously, so that is something to think about. The Iris are not as
efficient, but they are nice to look at. The water celery has a great root
system, and grows hardily in many zones. A nice blend of plants will give
you a nice look and give you good filtering.

Last year I jump started my VF with duckweed and watercress. The duckweed
eventually got eaten, but the water cress grew voraciously in my stream. Two
more great filter plants.

--
BV.
www.iheartmypond.com