The Marine Depot OF series overflow boxes allows you to add an overflow system for a sump, wet/dry filter or refugium. The hang-on twin box design eliminates the need for complicated tank drilling, sealing and trimming of the aquarium rim.

The black surface skimming box takes up minimal space inside the aquarium and blends into the background. The water level in the tank is set by adjusting the height of the skimming box then hand-tightening the nylon wing nut. The overflow boxes features a one-piece acrylic hanger that fits on any aquarium. It is pre-drilled and ready for installation of the bulkhead fitting.

They also come with vent tube assemblies and noise-reducing foam sleeve. This helps the water flow smoothly and quietly. The U-tube transfers water from the overflow, into the skimmer box and down to the external sump or refugium. The OF series boxes are easy to start up and priming takes only a few seconds – Just use an airline to suck out any air caught in the U-tube and the overflow is ready to go!

The Marine Depot Overflow Box will automatically restart after a power outage or if the return water pump is switched off and on for cleaning, feeding and maintenance. There are six models available to cover tanks between 30 and 320 gallons and flow rates from 200 to 1600 gallons per hour.