does anyone use bioballs or noodles in their canister filter insted of traditional carbon, I would like to creat a more biological filtration in my canisters
You can put any media you want in the media container. It is especially effective because when surrounded by the (blue) filter sleeve, it serves only as biological filtration.
You can use 'em, but the Mag 350 doesn't really hold a sufficient volume of biomedia to make them a great biofilter. Compare the volume to an Eheim or Filstar, and you'll get a sense of how small the media-holding capacity of the 350 is.