Classic 1000 HOB Protein Skimmer

The Reef Octopus Classic 1000 HOB Protein Skimmer is one of the most established hang-on-back skimmers in the hobby, built for aquariums up to roughly 130 gallons that don't have sump access. Its compact cylindrical body mounts externally on the tank rim, with the pump and reaction chamber positioned outside the display so it takes up zero display-side real estate. Best for: reef, FOWLR, and mixed saltwater tanks up to approximately 130 gallons Setup: hang-on-back, no sump plumbing required Pump: needle-wheel pinwheel pump for fine, stable microbubbles Maintenance: tall collection cup extends time between empties Because the pump sits outside the waterline rather than submerged in the display, the Classic 1000 HOB also runs quieter and cooler than many internal hang-on designs — a detail that matters on tanks positioned in living spaces. Compatible replacement parts: Classic 100/1000 HOB series pump kits and collection cups.