Is it real noisy? Take the top off, is there water coming up and into the filter compartment? If not, use a cup and pour water down the intake shaft til is starts suction. Mine is rather quiet, just the slight sound of water flowing through the biowheel.
As for the 2nd media cartrige, use either ceramic rings or lava granules, or even floss if you want. If using AC
, you will need to change it out regularly. The ceramic rings and lava granules you never need to change out, and floss will need regular maintenance so it doesn't get all plugged up.