Green Water in Pond

It's very hard to stop the water going green in high summer without resorting to UV filtration or chemicals; usually I would recommend growing water lilies to reduce the amount of light reaching the water but they don't like being continuously sprayed with water from a fountain.

Growing plenty of oxygenating plants like Elodea or Hornwort will help out-compete the green algae but probably won't "win" the battle completely if the pond is in an open, sunny spot.

The good news is that green water indicates that the water is healthy (albeit a bit high in nutrients) and goldfish don't seem to mind it one bit!

I have used the barley straw bricks in the past with moderate success, even made my own from old carrot bags from a large bag I'd got for horse, a mate let me use their straw foc.

The Canadian weed needs to be avoided as its rampant once it gets aclimatised and will take over the pond, choking it. Lilies are good, but in all honesty green water at high temp days is inevitable, my own horses bath of water turns green in a couple of days in this weather. Just keep taking out the filter on the pump and washing it out in clear water, when it rains the green will sink, and then almost disappear come autumn into winter.

Sorry I'm not much help, but thats part of the joy of having a healthy pond, without chemicals or expensive UV systems.


Oh, hang on....the UV thing can be achieved by making a rhyll, a small pond above the original with a shute between them letting the light do the UV bit naturally....thats how we did it! 

Do you mean duckweed ? I would not introduce duckweed to any pond as it can be a major problem in itself. The only time you will see any water is if the wind blows it all up one end.

As you say once you have duckweed you have it for life.

???Sorry don't know what happened there.

No, it's not duck weed, it lays on top of the water and is very easy to keep under control and the 'extra' goes on the compost    I also have had no luck with pond weed that's why I introduced this plant when the algae took over one year.

Duckweed floats on top forming a green carpet ,  little leaves and a dangly root shown here,
http://www.clean-flo.com/weed-algae-identification/duckweed/

Yep it's duck weed.  The one that died was long, green and under water