Hi Caryl,
I had the same problem. I used the inlet filter off a powerhead to solve the problem.
The type is Powerhead
The Model is 802
Get the filter cartridge that goes underneath the powerhead (you can buy it separately) and fit it to the fluval inlet.
You need to make a small spacer as the Fluval pipe is much too small for the filter outlet.
The fiber filter cartridge will evenually clog up and you have to throw it out (never had any success trying to clean them). Once this is gone, you need to replace it with something else. I use a fine plastic mesh tied over the outside of the filter. Every couple of weeks it needs to be cleaned, but it works really well. It also helps keep the Fluval cleaner for longer.