If you've got substrate, hardscape, etc in your tank, the beneficial bacteria you need attach themselves to the bio films that form everywhere. If your tank is in balance, you should be able to 'disturb' a filter and still have the tank maintain itself. Your filter media is of course going to house the greatest volume of BB.
I don't use filters with throw away media. I use mostly coarse sponge media in my canisters with exception of a few that have seachem matrix, ceramic rings, balls, etc as well as sponge. I also use AquaClear and Sechem Tidal HOBs. I rinse the HOB media in tank water. My canisters I use tap water and never have a cycle issue.