Help please - Green water!

Hi,
Moved into our house last year and we have a pond. Decided to get some
fish and some air plant things and it has never been the same since.
We've had really bad algae (which has now gone), and we have emptied
the pond, cleaned liner, everything, and we still have green water! We
have a pump, but at moment it is that blocked we are having to rinse
the filters every other day.

We've been told by different people that we need to put plants in it,
or get a UV filter. What kind of plants do you reccomend? Will the
resolve the green sludgy stuff or will it stop it getting worse? What
sort of set up is a UV filter and are they all the scary prices that
you see them at in garden centres?!

I'm brand new to all this pond stuff, but I really like having it and
would love for it to look nice again! Even worse, the cat keeps
drinking from it and then being horribly sick in the living room - any
advice gratefully received!


--
Weez