Aqueon Quietflow Filter X-Small - Media Replacement

Hello! I've recently set up a tank with two african dwarf frogs and a couple ghost shrimp.. I have an Aqueon Quietflow Filter in XS. I would like to use my own filter media and not exactly sure what I should use to replace the stock cartridge and how it should be set up inside. I've included some photos of the filter and my tank when I first got it. The top view photo is showing someone replacing the stock cartridge with a carbon polishing pad, but I posted that photo to show what it looks like on the inside for reference. Thank you for any help!

Looking at the filter on Aqueon's website, it says it contains only this cartridge. The simplest thing is to cut a slit in the cartridge and empty out the carbon. Keep the floss type bag on the frame. Cut down some sponge (any make) to the same size as the cartridge, hold the sponge and empty cartridge tightly together and put in the filter. Then just wash the sponge and the cartridge bag in old tank water.
You don't need to use carbon on a daily basis and sponge is a better medium than floss.