OK I'm looking to upgrade my filtration. I'm NOT sure of the differences between a sump and a fuge other than a fuge uses algae and you need a light on it preferrably on while your tank lights are off. Now besides that difference what IS the diference between them and their filtering? I don't wanna buy something that I'm gona have to replace ( like I'm doing now). PLEASE let me know what you guy/gals think about this and use.