The Red Sea REEFER S-850 G3 is part of Red Sea’s third-generation line of reef-ready aquariums. The “G3” series introduces improved plumbing, stronger glass, and better integration with smart control systems like ReefBeat.
The “S-Series” designates larger, deeper tanks compared to the standard REEFER models, offering more aquascaping and swimming space.

The black version features sleek, dark cabinetry and trim for a modern, professional look that suits most interiors.
When sold as a “complete system” or “plug-and-play” package, it includes key components like the sump, plumbing, auto top-off, and sometimes lighting and return pumps — depending on the retailer.

• Display tank dimensions: Approximately 70.9" long × 26.8" wide × 25.6" high, offering an expansive layout for advanced aquascaping and coral placement.
• Display volume: About 184 gallons of usable display water volume.
• Total water volume: Roughly 225 gallons, including sump and plumbing capacity.
• Sump capacity: Around 41 gallons, featuring an adjustable skimmer chamber and a refugium-ready design for flexible filtration setups.
• Glass thickness: 19 mm (¾ inch) ultra-clear, low-iron glass with beveled edges for exceptional clarity and strength.
• Stand height: Approximately 60 inches, providing a tall, elegant presentation and comfortable viewing height.
• Cabinet construction: Built from marine-grade laminated plywood with a reinforced aluminum super-structure, finished in sleek black with epoxy protection and stainless-steel hinges for maximum durability.
• Bracing: Euro-braced top design ensures extra rigidity and stability across the larger glass panels.
• Overflow and plumbing: Equipped with a low-profile overflow box, dual return outlets, and pre-plumbed, ready-to-assemble piping with Red Sea’s “ReefGate” precision valve for quiet and easily adjustable water flow.
• Filtration compatibility: The sump is ReefMat-ready, designed to integrate seamlessly with Red Sea’s automatic fleece roller, DC skimmers, and other filtration equipment.
• Auto top-off system: Includes the smart ReefATO+ system, offering automated water level management, built-in leak detection, and temperature monitoring for safety and convenience.
• Electronics panel: Comes with a slide-out control panel for tidy organization of controllers, power bricks, and cables.
• App integration: Fully compatible with Red Sea’s ReefBeat app, providing centralized smart control over all connected Red Sea devices such as lighting, pumps, and skimmers.
• Warranty: Backed by a 3-year standard warranty, extendable to 5 years upon product registration.