The Reef Octopus multi-filter allows water to flow evenly through the filter media increasing its effectiveness. While we recommend using Bio-sphere, various kinds of media can be used in this filter. Its screw open top along with all the connections makes this filter easy to install. Completely configuration, ready to be used. Matched a enough large pump to adapt multiple usages. External / Inner use in Sump. Multi fixation mode , easy to be placement. Double grid plates and sponge, ensure have no leakage of media and plug pipe. Convenient, connection fasten, no water leakage.