As said previously, the duckweed will absorb nutrients.
The nutrients therefore cause the weed to thrive.
Cut down the nutrients and the weed will not be so vigorous.
Since there are more nutrients in tap water (!) than in rain water,
don't use tap water to top the pond up. If the pond needs constant
topping up - find out why.

--
ned


"cineman" wrote in message
.uk...
Hi
It sounds like duckweed, this will become a nuisance and take over a
pond
very quickly, However it does have its benefits, It will take excess
nutrients out of the water and stop the pond from turning green,
"Green
water becomes short of oxygen, as I understand it" but it keeps the
water
much clearer, if you net it out be careful about tadpoles, and leave
any
surplus on the edge of the pond for any aquatic creatures such as
fresh
water shrips to climb back in.
Check over each net to return any tadpoles to the pond

Regards
Cineman

wrote in message
...
Hello,

As I said in another post, I've moved house and there is a pond in
the
garden. The pond seems to be full of weed (and tadpoles - but
that's a
different post). I think it is duck weed? It looks like tiny
single-leaved plants that float on the surface of the water. I
think
this spreads manically. Should I remove it all before it covers
every
inch? Is the best way to do this with a net, or do I have to
resort to
chemical means? Will it cause problems by starving the other
plants or
blocking the light into the water?

Thanks.