i am looking into getting an octo but. through my reading sites an stuff and people helping me out on this site it has come to my atention that the filter that i have will not work for an octo becuase i cannot seal around it .. Right now i have an Emporeur(sp) 400 with the dual bio wheels.. so it is almost impossible to make a seal so i think i am going to use that one to filter my feeder tank.. But my real question is what kind of filter do you people use? what should i look for in a filter? how many will i need? i was thinking about using a Fluval 404 which is rated for a 100 gallon tank and filters 340 gph... Also my tank is a 75 Gallon..