"Anonny Moose" wrote in message
...
This may not be the correct forum to ask about this, but I figure a lot
of
people have concrete bird baths in their gardens. One of my bird baths,
it
is concrete, grows some sort of red crud that discolors the water. It
actually cakes on the surface when there is water in it and can be
chipped
off when it dries. My other concrete bird bath doesn't do this. Any idea
what it is and what's causing it? Is it harmful to birds? Any way to get
rid
of it?

Thanks in advance.
Karen
Portland, OR

Sometimes the iron in hard water causes a red sludge in my concrete bird
baths. swh