I need a better filter/pump for my small pond. Advice please?

[Kabuki]

Heyo! My 90 gallon pond is an above-ground 4X3X1 square. I have a 22 gallon tub with a spillway for a waterfall that pours into it that is fueled by this tiny Catalina 900 filter/pump that is doing a really lousy job. It makes a nice fall, but it lacks filtering power.

Now that my new hobby is almost a year old, I'd love for some of the ponders to tell me what is the most efficient and affordable pond system I can purchase so that the water is good, clear, and healthy for the fish without blowing my water lilies out of the water!

Also, my water is nasty in Northern California. For water changes, what is the recommended system I should be using with a hose? I know nothing at all about water treatment and I need to step up. Thanks very much.

[Kat]

What are you using for filtering materials inside the tub?  I've got one set up similiar but I've made it Skippy style.
http://www.skippysstuff.com/biofiltr.htm

I'm using bricks on the bottom, eggcrate, layer of poly cut it yourself furnace filter, bath scrubbies, another layer of furnace batting on top, & then a basket to hold floating plants.

[Julles]

Think about getting a second pump.  Continue to use the one you have, to run the pretty waterfall and aerate the water. 

Then you could use the other to operate a Tetra non-pressurized bio filter.  About the size of a 5-gallon bucket.  I had one for years and it worked great.  It is not pressurized, though, so that means the water must feed by gravity into your pond, and so the hose going to the pond has to be down below the surface.  That's why you still need your original set up to splash into the pond and add oxygen to the water.

I recently saw a set-up similar to what Kat described.  Simply some filter media set at the edge of the spillway, so it caught gunk before it went back into the pond.  That might work OK for a few goldfish, but if you move to koi, or overcrowd your pond (as most of us do), you will need a real filter. 

[Kabuki]

Since I'm not really as adept at building things as some of these creative DYI'ers are, I think the Tetra biofilter may be a better choice. Is a Tetra ClearChoice PF-1 Filter 500 GPH big enough for my pond? I see one on ebay for $29.00, never used, free shipping.

I added another pump that I had, and then added two lilies and a couple of water hyacinth and in two days it is by -far- much cleaner and the fish are perky and swarming all over the place. My small wakins have to really hustle to keep up with the fearsome five.

Thanks so much for everyone's advice. 

[Kabuki]

Ok! I purchased the external biofilter, got the right hoses and now need a pump to run it. It will be filtering a 90 gallon pond and an overflow bucket of about 20 gallons. I don't want it to take up too much space in the water with the fish, and I'd like it to be affordable. Suggestions?