Eheim 2215 With marine pure bio balls and sponge. There's still a little room left for additional bio media or a polishing pad. $50
Also selling eheim pro 4+ 350 all original parts and media. Only plugged in once to test. $160
Hey guys, was perusing Home Depot and stumbled upon some expanded clay - a media usually used to grow hydroponic plants. Sometimes called Hydroton (the kleenex of expanded clay).
It costs <$10 for ~10lbs of the industrial biofiltration media of choice
(as in this study on denitrifying...