When I set up my tank I am trying to debate on getting a skimmer or fleece roller first. This is my first SW tank so I may not even be asking the right question. They both seem to do roughly the same thing. It would seem that the skimmer would remove smaller particles from the water as opposed to the fleece roller. I plan on having a mixed tank and my tank is roughly 104 gallons with a 40 gallon sump.