Reddit mentions of Aquarium Biochemical Cotton Filter Foam Fish Tank Sponge 50x50x2.5cm by liannmarketing

Get something like This to replace your mini white filter pad inside the filter. Just cut it to fit into your filter. To clean it all you will have to do is take it out and shake it in a bucket of tank water when you are doing a water change and squeeze it a few times. Also an API master test kit will be useful to keep water quality great. If you are using city water i would suggest a 5 gallon bucket to either age your water for 24 hours or mix in the dechlorinator before you add the new water into the tank as 5 gallons every couple of days. Me personally i would change 3-5 gallons of water every day for the next 40 days or so which can be tedious but until you get a colony of bactera built up the ammonia/nitrite can spike fast. Also a Gravel vac or some kind of tubing to siphon water out.

I bought a large piece of filter sponge Planning on cutting it to size and trying that out. The water will be able to pass through and its a good surface for good bacteria to chill. I'm going to see how it does, if it works out and my current betta can't get around it then I'll get a second betta :)