What filter should I get for a 30g tank? Or none?

[thered]

I have a Seaclone skimmer and I was wondering what filter to add to it. Or should I just run the skimmer alone?

 

[logan15]

IMO i like my bio wheel it helps remove ammonia and nitrites faster for me but as i said that just IMO, i also have a seaclone skimmer i like it alot do you like yours?