Eshopps Refugium R-100, 75-125g, 2nd Generation. Refugiums are one of the most efficient ways of filtration in saltwater aquaria today. Not only is it a natural way to filter your display tank but it is a sanctuary for micro-organisms to flourish and reproduce. The Macro-algae used in the refugium will utilize nitrates and phosphates from your water column. These algae’s uses these nutrients to grow and thrive. Eshopps R-100 Specifications: • High quality acrylic refugium filter with unequalled value • First Compartment is 7" x 11.5" to fit in-sump protein skimmers. • 1" threaded inlet with prefilter bag • Rated for tanks up to 125 gallons • Dimensions: 24L x 12"W x 16"H