trailer gal I don't know the specs of your filter or filter material. But many of use use washable filter furnaces from Home Depot or Lowes as replacement filter material. Just be careful to not get the fiberglass type as they break down very quickly. The types of filter media are layered by thinner density to thicker. You can search on the web for pond suppliers that sell media. Matala media is very good but pricey and if you look that up you can see how the different colors relate to density of the material.

I have the 1000 model in my 200 gallon pond. It came with both the black and white filters.

The black filter has a little bit of carbon in it. I'm not a believer in carbon filters for fish but I buy a new one each spring as they just look ratty to me. I don't think it has enough carbon to work for more then a week or so, but I get it anyway.

The white filter is just to screen out muck. I usually replace that too every year.

BOTH filters provide a place for good bacteria to grow.

As my filter tends to get clogged with muck 1-2 times a week I also use batting as a pre-filter to catch the muck. You can get that at a craft store, it is used for pillows and blankets as stuffing. Lately I've switched to foam sheets as it is a bit more durable then plain batting.

I keep the black in the bottom, then the white, and lastly the batting on top. When I clean the filter every 3-4 days I just take out the top batting and replace with another dry piece of batting. The other pieces I try to leave along so not to kill the good bacteria in there.

I keep 2 pieces of batting so I can rinse one off and leave to dry a few days before putting it back in to keep chlorine out of the filter.