A remote (i.e., sump-based) filtration system is standard for most reef tanks, for good reason.  Remotely locating the filters saves valuable space in the display tank while hiding unsightly hardware out-of-sight. Feeding the sump tank with water skimmed from the surface of the display tank keeps the air-water interface of the display tank free from lipids and proteins that can prevent gas exchange, and provides the filters in the sump dirty water to work on.

In the display tank itself, a large quantity of live rock and live sand provide a large surface area for nitrifying and denitrifying bacteria. A portion of the sump tank is set aside for a refugium of macroalgae (illuminated in a reverse-photoperiod arrangement) for nitrate and other nutrient export. The majority of the water from the display tank is fed to the skimmer section of the tank (through a filter sock), where it is fed in turn to a large protein skimmer driven by a controllable DC pump, and to an external filter manifold driven by another controllable DC pump.  

The filter manifold provides water to a number of external reactors, including an ozone reactor (controlled with feedback from a oxygen redox potential sensor), a carbon reactor for post-ozone filtration, and a granular ferrous oxide (GFO) reactor for removing phosphtes.  The ozone reactor is fed ozone from a 200mg/hr ozone generator, which receives feed air driven by an airpump through a custom air dryer.