This canister filter is an unique streamlined design, with the efficient use of the entire canister volume. This is self priming by only pressing the attached piston part to exclude the air and indute the water into the canister to effect the operation. Very easy to use and just turn the close lock for both the in and out valve tap and the cavity is easily remove for cleaning. This product adopt super quality of Dolphin Series immersible pump which is less energy consumption, more reliable operation, also provide longer life and low in noise. It filter through different media and improve the reproduction of beneficial nitrobacteria. The structure of the pump head is wonderful since it allows for simple operation and cleaning.