The Freedom Reef Sumps are specifically designed for saltwater systems. They are easy to use and inexpensive to maintain, utilizing the standard 4 inch 200 micron bag. Our proprietary bubble diffuser tubes on incoming water flow minimizes noise while removing bubbles for better flow through the filter system. Includes flexible hoses, bulkhead fittings on sump, 4 inch Micron bags and the foam block sponge. (Chemical Media Cartridges are optional and not included).