need help choosing filter

Hey i need assistance choosing a filter for my pond.

its roughly 1500 gallons
we have 9 koi, ranging from 3inches up to 30 inches, 2 6 inch goldfish

we have a little giant pump <which also needs replaced at some point, so reccomendations for that would be appreciated as well>

we have 2 waterfalls that feed into the pond.

I was looking at this filter http://www.123ponds.com/a50019.html, as reccomended by our local Koi store, but i would like to see if someone else knows of a filter that would be just as effective, but less expensive so maybe we could buy a better submersable pump as well. I dont think a UV will be needed for my pond because its in relatively shaded area.

coelus

If you are handy with tools and can search the internet, there are inexpensive ways to build your own filter and pumps over 3000 GPH can be had for less than $100.