Well I'm not familiar with that particular filter but I haven't seen anything like that in a saltwater tank before, if it has balls or filter floss in it, it will eventually become a
nitrate factory and lead to bad things. If you want to keep coral you will definitely need to upgrade the lighting. I would get rid of the air pump to keep from causing major salt creep issues, as well as problems with micro bubbles. An external pump is only necessary if you plan to use a
sump. This is something that is generally recommended because it allows you to keep all of the unsightly equipment out of sight. If you go this route it will also add the need for some plumbing parts as well as a container for the
sump itself etc.
