Best biological filter media for my Fluval 305?

sponge on one side as it shows in the pic , and then in my baskets i use pot scurbbers , so in bottom basket 2 surubbers and middle basket 2 more scrubbers top basket is left for what ever you want to put in it
 
ohh ok i gotcha, i have the 4 sponges.

I went looking for pot scrubbers and the ones i found came in a 3 pack, they were large and couldn't fit well so took them apart lol I filled the top two baskets with them. Hopefully i can find some smaller ones.
 
You got a better deal then me lol, i got them 3 for a dollar.

Im trying to find the ones that come in a 6/8 pack, they are smaller then the monsters i got lol
 
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