UV filter + material

Hi
I am a newbie here and I need some advice about filtration.
I have a small pond approx 2m x 1.5m x 0.5m with an underwater pump and
a small waterfall.
It has no fish(I may want to add a few later) but some lillies and a
couple of other oxygenating plants. Sounds pretty basic, I guess, but
my water is all green - can't see a thing below the surface.
After Googling for a while, I think I need a material filter(beads?)
and a UV filter to kill the algea.
The area around my pond is not suitable for underground filtration, so
I need an in-pond underwater solution.
So, can anybody recommend a combined material/uv underwater filter that
I can buy in the UK? My pump has a 1"(25mm) inlet/outlet.

Or, maybe there's a different solution?




--
blobby