[Goosegirl]

I have a lovely water feature that has two waterfalls. At the top is an old tree stump rescued from the shore but it has increasing amounts of moss growing on it. Although the stump is nice, the moss from it has spread onto the rocks and cobbles and is currently coating all those under the water as well as those that are exposed. What is your advice?

[JayG]

Although there are algicides available for water features which may also kill moss, even with no fish I'd worry about what else might be harmed (natural water inhabitants, birds, dogs and cats.  )

I'd try to remove it by hand (probably have to drain it down first.)

[gobs]

It must look lovely!

[Goosegirl]

Thanks JayG - but easier said than done! I have removed some clumps by hand, but there is a lot that is lying flat and "strung out" on top of the stones that just won't come off them. I do believe that many of the water treatments for green water, duckweed probs etc are ok for wild life or I wouldn't use them, especially with my cats who sometimes drink out of it. I have used one for green water and my little froggie was fine as well as my cats. I'm attaching a pic of it before the moss grew - now all the central part is a dark green colour and I can't see the lovely colours of the stones anymore. Bum - my pic won't open larger so will try and post it again shortly.

[JayG]

Nice water feature GG! 

I suppose the real problem is that permanently damp/wet stonework provides the ideal conditions for certain types of algae to flourish, and there are so many different types that one formulation may not deal with everything even if continuously replenished.

Have you seen this RHS article? - some useful information and tips on the subject and a few other possible 'cures.'

[snowdrops]

Nice water feature.  your picture opens bigger for me 

[Goosegirl]

Here's another one - hope you can see it properly. Modifying this post, I can't - bummox!

[gobs]

Very nice. I am not surprised you do not want to scrape it by hand.

[Goosegirl]

Very nice. I am not surprised you do not want to scrape it by hand.

This is the trouble - it won't scrape off unless I try a knife or something.

[Tracybutton]

Try barley straw as it seems recommended by a lot of people.

http://www.chemungcountyswcd.com/Barley%20Straw.htm