On 27/5/2003, Gayle Benton wrote:

>I have a little cement pool built into some natural rocks used solely for
>the birds and they love it. Even though it has a circulating pump, the
>algae builds up very fast. Does anyone know of something that will prevent
>this growth without being toxic to the birds? Thank you in advance.

How big is it? Is there room for a small pot or two of pond plants?
Those will use up some of the available nutrients and slow down the
algae a bit. Something like Veronica americana may leave it's pot and
peregrinate around the pond, and some of the little birds like to perch
on the Veronica runners while they drink and splash. Plants can also
help shade the surface so the algae gets less light. Won't stop it
completely. But you can also think of the algae as a resource--it
makes great fertilizer! When the algae gets thick enough, I scoop it
out and give it to whichever nearby plants would like a boost. If the
veronica or other pond plant gets uppity, it can be put to the same
use, though since many can survive outside of a pond, you may want to
let it dry out before using it as mulch.
--
Allyn Weaks allyn at tardigrade.net Seattle, WA Sunset zone 5
Pacific NW Native Wildlife Gardening: http://www.tardigrade.org/natives/
"The benefit of even limited monopolies is too doubtful, to be opposed
to that of their general suppression." Thomas Jefferson