Red Sea Reefer S-850 G3 - Black Cabinet

The Red Sea Reefer S-850 G3 - Black Cabinet is a premium 850 litre / 224.5 gallon reef-ready aquarium and cabinet system for aquarists who want a large 180 cm REEFER-S G3 display with a black aluminum super-structure cabinet and split-sump filtration platform.

This base REEFER-S system is built for serious reef keepers planning a large custom aquarium with intentional equipment selection. It includes a euro-braced 19 mm ultra-clear glass display, heavy-duty black aluminum cabinet, replaceable panels, slide-out control panel, split REEF-SPEC sump with main and extension sections, ReefMat-ready mechanical filtration, ReefGate precision valve, central overflow with removable surface skimmer, curved dual returns, pre-assembled plumbing, and integrated ReefATO+ smart top-off control.

Red Sea REEFER S-850 G3 Black Reef System

• Large 180 cm reef display: The S-850 G3 gives reef keepers a long display footprint for multiple coral zones, natural fish movement, and showpiece aquascaping.
• 850 litre total system volume: The 224.5 gallon volume supports strong stability, larger coral colonies, and more advanced filtration planning.
• Black aluminum cabinet: The black super-structure creates a premium high-contrast installation while providing a rigid support platform.
• Split sump design: The S-850 includes a main sump plus extension section for extra filtration flexibility, refugium use, frag capacity, or other planning needs.
• Custom equipment freedom: Return pumps, lighting, skimmer, heater, wavemakers, dosing, and automation are selected separately.
• Advanced Red Sea ecosystem platform: The system is ready for optional ReefRun, ReefLED, ReefWave, ReefMat, ReefDose, REEFER skimmers, and ReefBeat-connected hardware.

180 cm Euro-Braced Ultra-Clear Display

• 680 litre display volume: The main aquarium provides 179.6 gallons of display space for a mature reef aquascape, larger coral structures, and carefully selected fish.
• 180 x 68 x 65 cm dimensions: The long 180 cm format and 68 cm depth allow island reefs, broad ledges, negative-space layouts, and multiple coral zones.
• 19 mm glass construction: The S-850 G3 is listed with 19 mm front, side, bottom, and back glass.
• Euro-braced large-system support: The braced format reinforces the large display while maintaining a clean professional profile.
• Ultra-clear viewing: Low-iron glass improves clarity across the large viewing panels and helps coral colour show more accurately.
• Showpiece scale: The 180 cm length makes this model suitable for dedicated reef rooms, large living spaces, offices, and showroom-style installations.

Black Cabinet and Slide-Out Control Panel

• Heavy-duty aluminum super-structure: The cabinet is built around a rigid aluminum support frame designed for large reef systems.
• Replaceable black panels: The exterior panels create a clean finished look while retaining the modular REEFER-S cabinet design.
• Hidden adjustable feet: Leveling feet support proper installation on suitable flooring without disrupting the cabinet appearance.
• Slide-out control panel: The integrated panel helps organize controllers, power supplies, dosing hardware, and smart devices.
• Large equipment area: The cabinet provides space for the split sump, controller planning, cable routing, dosing equipment, and future upgrades.
• High-contrast presentation: The black cabinet visually frames reef lighting and coral colour while concealing the equipment area.

G3 Flow System and Dual Return Planning

• Optimized G3 plumbing: REEFER-S G3 water management is designed for stronger and more efficient water circulation.
• Quiet downflow: The rectangular downflow inlet reduces turbulence and supports quieter operation.
• ReefGate precision valve: The drain can be finely adjusted for a stable overflow level and near-silent sump operation.
• Surface-skimming overflow: The central overflow includes a removable surface skimmer for improved water-surface management.
• Curved dual returns: Dual return outlets help distribute water across the 180 cm display and support a single or dual return-pump strategy.
• Pre-assembled plumbing: Included pipework keeps installation clean and reduces custom plumbing guesswork.

Split Sump, ReefMat Readiness, and ReefATO+

• 170 litre sump volume: The split sump provides significant space for skimming, media, probes, return pumps, dosing lines, and future filtration upgrades.
• Main plus extension sump: The extension section can support additional filtration planning, refugium use, frag space, or flexible equipment layout.
• ReefMat 1200 ready: The mechanical stage includes micron socks and media cups and is designed for an optional Red Sea ReefMat 1200.
• Integrated ReefATO+: ReefATO+ helps maintain stable water level and salinity while adding temperature monitoring and leak detection.
• Large-system filtration flexibility: The sump can support skimming, carbon, reactors, refugium-style nutrient export, dosing, and monitoring equipment.
• Advanced service access: The cabinet and split sump layout make maintenance and future equipment additions more manageable.

Red Sea Reefer S-850 G3 Black Specifications

• Total system volume: 850 L / 224.5 gal.
• Display volume: 680 L / 179.6 gal.
• Sump volume: 170 L / 44.9 gal.
• Display dimensions: 180 cm L x 68 cm W x 65 cm H / approx. 70.9 x 26.8 x 25.6 in.
• Total height with cabinet: 153 cm / approx. 60.2 in.
• Glass thickness: 19 mm front glass, 19 mm side glass, 19 mm bottom glass, and 19 mm back glass.
• Display format: Euro-braced ultra-clear glass aquarium.
• Cabinet: Black aluminum super-structure cabinet with replaceable panels, hidden adjustable feet, stainless hardware, and slide-out control panel.
• Filtration: Split REEF-SPEC sump with main and extension sections, mechanical chamber, micron socks, media cups, ReefMat-ready layout, and integrated ReefATO+.
• Recommended return pump: 2 x Red Sea ReefRun G2 12000, sold separately.
• Recommended lighting: 4 x Red Sea ReefLED G2 170, sold separately.
• Recommended ReefMat: Red Sea ReefMat 1200, sold separately.

Application Notes for the REEFER S-850 G3

• Best use: Ideal for large mixed reefs, SPS-capable systems, LPS displays, soft coral aquariums, and premium showpiece reef installations.
• Equipment planning: Plan return pumps, lighting, skimmer, heater, wavemakers, optional ReefMat, dosing, and monitoring before filling.
• Lighting planning: The 180 cm length and 68 cm depth require a multi-fixture lighting plan based on coral goals and aquascape height.
• Flow planning: Dedicated wavemakers are needed for reef circulation beyond return flow.
• Not included: Lighting, return pumps, protein skimmer, heater, wavemakers, livestock, rock, sand, salt, optional ReefMat, dosing equipment, and test kits are sold separately unless otherwise stated.

Red Sea REEFER-S G3 Series Video

Setup and Installation Notes

• Assemble and level the cabinet: Build the black aluminum cabinet according to Red Sea’s instructions and confirm the system is level before placing the aquarium.
• Plan the equipment package: Choose return pumps, skimmer, lighting, heater, wavemakers, ReefMat, and controller layout before filling.
• Use the slide-out control panel: Mount controllers, power supplies, and dosing equipment early for cleaner access.
• Install split sump and plumbing: Confirm the main sump, extension sump, overflow, ReefGate valve, returns, and ReefATO+ are correctly installed.
• Freshwater leak test: Test the full system with freshwater before final saltwater setup.
• Tune the ReefGate gradually: Adjust the valve slowly until drain noise and sump level are stable.
• Use RO/DI water: RO/DI water is recommended for saltwater mixing and top-off.
• Cycle before stocking: Establish biological filtration before adding livestock.

What’s Included

• Euro-braced 19 mm ultra-clear glass aquarium
• Black aluminum super-structure cabinet with replaceable panels, hidden adjustable feet, stainless hardware, and slide-out control panel
• Split REEF-SPEC sump with main and extension sections, mechanical chamber, micron socks, and media cups
• Pre-assembled downflow and return plumbing with ReefGate precision valve
• Central overflow with removable surface skimmer
• Curved dual return nozzles
• Integrated ReefATO+ sensors and controller

Shipping Notes

• This item is exempt from our free shipping policy.
• To avoid delays, please order Red Sea aquariums by themselves. If you are wishing to order multiple things, please place two separate orders: one for the aquarium and one for the rest of your products.
• Please call for a shipping quote if ordering from NWT, YK, or NUN.
• All Red Sea aquariums are brought in and shipped out on an as-ordered basis. The average turn-around time to ship an aquarium to you is two business days, except where noted below.
• All shipments outside of the Vancouver area are shipped via trucking company with residential and power tailgate delivery, and are fully insured.
• Tanks ordered within BC and, in some circumstances, Alberta may take an extra 5-10 business days to process. Systems ordered from Alberta and east of there usually ship within two business days direct from the distributor in Ontario.
• If you are ordering for pick-up from our store, please select in-store pickup to avoid delivery charges. You will be notified when the tank arrives, usually within 5-10 business days.
• Red Sea Max S Series aquariums are always special order and will take from 3-6 weeks to ship.
• Please note the freight company is only responsible for getting the aquarium to the destination address and off-loading it. They are not responsible for carrying it inside.
• All freight charges have been greatly subsidized to help you get up and running with your new Red Sea system.