It's the algae thats passed through your UV. After the UV the algae
clumps together and sinks in the pond to form the green powder.

Jon
"Sue Alexandre" wrote in message
...
I know I should probably know this answer since this is my third year with
my pond, but what is that green, powder-like substance that rests on
everything in the pond? If you pass anything over it, even a big fish,
it
all disperses into the water making it temporarily green and cloudy, and
then settles back down again, on whatever. Is this dead algae? Live
algae? I catch tons of it in my quilt batting (changing it almost daily)
but it still just keeps on coming! My pond is about 4000 gallons, I
have
a biofilter, waterfall, skimmer, and UV. The water looks great, but the
green powdery stuff is really annoying. I did suck up (or try to) a lot
of
it with a shop vac last weekend, but now it's all back. Is this the dead
algae that's being killed by the UV????? Any solutions?
Thanks in advance.
Sue