Live rock and sand will definitely hold much of your bacteria, but incorporating the additional filter media in your canister is a great place to populate massive amounts of beneficial bacteria. You should shop around and see if you can get some type of sintered glass over seas, the company i mention does usually deliver by mail so it might be possible? If you watch that canister filter setup guide video, he explains how you want to trap the detritus and waste in the bottom of the filter so it doesn't clog up your filter media in the upper trays. Polishing pads are going to remove very very fine particles, but a skimmer is a step above IMO. You don't have to have a skimmer, but i highly recommend it.