Magniflow Canister Filter makes multi-stage filtration faster, easier, and better than ever. This powerfully designed filter offers a variety of upgrades that make both freshwater and marine aquarium success quick and easy. Be sure to seal the gasket in Cannister Lid. Failing to install the gasket or not installing gasket ring snuggly can cause the filter to leak. The Quick Prime Button fills filter chamber with water for self-priming system startup.