Not sure what you mean about the filter... it has three seperate compartments, and each one is devided in half. i keep mine like this... 2 corse, 1fine and 1finer sponges. then in the next ones, ciramic rings, then ehimes little balls?, then carbon/phosorb then 2-3 fine pads, like filter wool.
hope that helps.
edit: and this is on my 90G with 15 large millawies