Sump space is often the tightest constraint in a build, and moving a skimmer's reaction chamber entirely outside the sump frees up that space for other equipment. The Reef Octopus Classic Recirculating External line pumps water up into an external chamber and returns it, keeping the sump itself clear.
Why Go External
An external, recirculating design pulls water from the sump, processes it in a chamber that lives outside the cabinet footprint, and returns the treated water — freeing up sump real estate for reactors, dosing equipment, or simply a less crowded cabinet.
Choosing a Size
- Classic 110ext — the smaller external option, moving the 110-class reaction chamber entirely outside the sump.
- Classic 150ext — pairs the larger 150-size reaction chamber with the same external, recirculating design for bigger tanks.
Setup Tips
- Plan cabinet space for the external chamber before ordering — it needs to live somewhere outside the sump, typically in the stand.
- Account for the recirculation plumbing when planning your build, since water needs a path up to the chamber and back.
- Break in gradually like any new skimmer, with expected microbubble overflow in the first week or two.
The Reef Octopus Classic Recirculating External line is available at Marine Concept Supply — order online or pick up at our shop in Wheeling, IL. Shop 110ext or 150ext, and browse more protein skimmers.
