On Sat, 22 Nov 2003 22:17:31 -0000, "Mary Fisher"
wrote:




"Robert Wallace" wrote in message
...
I have a small pond I keep for frogs and wildlife.
Each year it gets covered with a thick layer of duckweed that causes the
water to become dark and evil smelling.

I'm surprised at that effect, my duckweed has no effect on the water.

It starts to grow when the water gets warm and then turns nasty.

The whole IJsselmeer does it some years.


As soon as the water temperature drops it disappears.

--
Martin