Best Seller | L Shape Sponge Filter, L150, 40 gal/hr These air operated internal filters work as a mammoth or airlift pump. It is pushed into the standpipe via a hose by an air pump. The air draws aquarium water upwards with it in there, water flows back through the fine mesh sponge that provides an... ... more L Shape Sponge Filter, L150, 40 gal/hr These air operated internal filters work as a mammoth or airlift pump. It is pushed into the standpipe via a hose by an air pump. The air draws aquarium water upwards with it in there, water flows back through the fine mesh sponge that provides an... Petco.com | | $19.99 go to store |