I run a rena XPL(XP3) on a 55gal. Three baskets, bottom basket has two #20 and two #30 foam pads, middle basket has 43bio stars and top basket has two fine and two extra fine pads. That takes car of my mechanical and biological filtration. I also have a bio chem sorb pouch that I have not used yet. I purchased it from American Aquarium Products online. So far it has been it a great filter and no issues in the short time I have had it running.