Aquarium sumps are the best way to do filtration in a saltwater aquarium or reef tank.  Filter Sumps like the Trigger Systems or other brands we sell use filter socks and other methods of removing detritus and waiste.  Sumps do not have to be used on just reef tanks with coral and fish, but can also be used as a fish tank sump for fish only systems.  

Reef sumps are the best way to add a refugium to your system, and also makes it easy to keep your display aquarium clear of equipment and filters.  When using a reef sump you can add macro algae like chaeto in the refugium section, plus they have areas for protein skimmers, heaters, filter socks, PH and temp probes, and all the accessories you would want to put down in the sump.  Aquarium sumps also allow more water volume in your system making them more stable for parameters.