martin wrote:
On Fri, 26 Aug 2005 18:27:04 +0100, "Bob Hobden"
wrote:


Once in a pond it's almost impossible to eradicate it without emptying the
pond, letting it dry, scrubbing it out, letting it dry, and carefully
washing all plants before you put them back. One piece not seen and it's
back to square one again.

So what makes it appear and disappear? Water temperature, oxygen
content? Some years the IJsselmeer is carpeted with the stuff, other
years not.
--
Don't know, only guessing, but maybe if it rains a lot there is soil
washed into the water and so more nutrients.

--
Jo