The Marin 500 filter system is designed for use inside the aquarium. It consists of a filter tank with dimensions of 19" x 8" x 26" (including foam cup). Water is fed to the protein skimmer chamber by way of a surface overflow and pre-filter sponge.

The motor driven protein skimmer is supplied with a patented Needle Wheel pump (Ocean Runner PH 2000 18 watt). From there it is pumped to a biological trickle filter, filled with Bactoballs. A Dosing Pump SP 600 supplies water to the Nitratereductor. An Ocean Runner PH 2000 (500 gph) pumps the water back into the aquarium. With the Marin 500, an existing tank can be transformed into a powerful salt water aquarium without any external plumbing or modification. For aquariums up to 125 gallons.