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Overflow Boxes

An aquarium overflow is a necessary part of an aquarium sump plumbing kit. If you want to run an aquarium sump but don’t have a reef ready aquarium, or a drilled aquarium, then your aquarium sump plumbing will need to include an overflow box (we also sell overflows for drilled tanks). The overflow box hangs on tank. The inside half is a surface skimmer that draws protein rich water from the aquarium. A siphon establishes water movement. On some overflow boxes, an aqua lifter pump helps to create or reestablish siphon after power outage.

The external half of an overflow box is a gravity drain that sends water to your sump via an aquarium drain hose. A return pump then delivers water back to the display aquarium. As the water level rises inside the display aquarium, it cascades into the overflow box, completing the aquarium overflow plumbing loop.


Marine Depot Overflow Box OF-800
Marine Depot Overflow Box Nano
Marine Depot Overflow Box OF-300
CPR 1-1/4 inch Drain Hose
CPR CS102 Overflow Box
CPR CS50 Overflow Box
Eshopps Overflow Box Eclipse - M
CPR CS90 Overflow Box
CPR CS100 Overflow Box
CPR CS202 Overflow Box
Eshopps Overflow Box Eclipse - L