Red Sea Reefer S-850 G3+ - Black Cabinet

Red Sea Reefer S-850 G3+ - Black Cabinet

The Red Sea Reefer S-850 G3+ - Black Cabinet is an 850 litre (224.5 US gallon) premium reef-ready aquarium system featuring a 680 litre (179.6 gallon) eurobraced ultra-clear glass display, a 170 litre (44.9 gallon) combined split-sump filtration system, and a black marine-spec cabinet built around a rigid anodized aluminum superstructure. Measuring 180 cm (70.9 inches) long and 68 cm (26.8 inches) from front to back, it provides an expansive six-foot reefscaping platform for large coral colonies, separated rock formations, and carefully planned marine livestock.

The S-850 G3+ combines 19 mm ultra-clear front glass, upper eurobracing with additional bottom reinforcement, dual 32 mm return outlets, and a precision ReefGate overflow valve. Its distinctive split-sump design adds a configurable glass extension sump for filtration, refugium, or independent reservoir applications. ReefControl Pro and the ReefControl ATO Module provide connected freshwater top-off and temperature monitoring, while lighting, return pumps, protein skimmer, wavemakers, and other equipment can be chosen individually.

Red Sea Reefer S-850 G3+ Black Aquarium Construction

• 180 cm (70.9 inch) display length: The six-foot aquarium accommodates multiple rock islands, open swimming channels, and separate coral placement zones without requiring all livestock and aquascaping to occupy one central structure.
• 68 cm (26.8 inch) front-to-back depth: The generous footprint allows rockwork to be arranged in layers, with room for branching corals, open sand areas, and circulation behind larger reef structures.
• 680 litre (179.6 gallon) display: The substantial main aquarium provides space for mature reefscapes while locating filtration and supporting equipment below the display.
• 19 mm (0.75 inch) ultra-clear front glass: The low-iron viewing panel reduces the greenish tint associated with conventional glass, helping present coral colours and marine fish more naturally.
• Eurobraced and bottom-braced construction: Perimeter reinforcement, additional bottom bracing, and high-quality euro-silicone provide structural support for the large glass aquarium.
• Black anodized aluminum cabinet: A rigid marine-spec superstructure supports the aquarium, with replaceable black exterior panels and concealed heavy-duty adjustable leveling feet.
• Custom equipment flexibility: The standard REEFER-S G3+ package includes its aquarium infrastructure and controller hardware without requiring the complete lighting, skimming, and circulation equipment supplied with a MAX configuration.

Premium Aluminum Cabinet and Slide-Out Control Panel

The REEFER-S cabinet uses a structural anodized aluminum frame with removable exterior panels, providing a different installation platform from Red Sea's conventional plywood cabinet systems. The S-850's cabinet accommodates its split-sump filtration arrangement while also providing a designated area for controllers and other compatible electronics.

• Marine-spec aluminum superstructure: The supporting frame is designed for the substantial glass aquarium and sump installation, rather than relying solely on decorative cabinet panels.
• Replaceable black panels: The modular exterior provides a dark furniture-style presentation while allowing panels to be replaced independently of the structural frame.
• Hidden adjustable feet: Heavy-duty leveling adjustments help establish uniform support before filling the aquarium.
• Slide-out control panel: A dedicated mounting surface provides organized access for compatible controllers, dosing pumps, power equipment, and wiring.
• Separate auxiliary equipment space: The cabinet includes an additional compartment for compatible chiller equipment and accessories. Equipment dimensions and ventilation requirements should be confirmed before installation.
• Service-friendly layout: Planning the sump, freshwater reservoir, electrical equipment, and optional dosing hardware before assembly helps preserve access for regular cleaning and maintenance.

Split-Sump Filtration with Multipurpose Extension Sump

One of the S-850 G3+'s most useful features is its two-part sump arrangement. The professional main REEF-SPEC sump contains the core mechanical filtration, skimmer, and return equipment, while the separate glass extension sump provides flexibility that is not available on the smaller S-550 and S-700 systems.

• 170 litre (44.9 gallon) published combined sump volume: The main and extension sump arrangement provides substantial filtration capacity when configured as part of the circulating aquarium system.
• Connected extension sump: The glass extension can operate with the main sump to provide additional filtration volume, a larger refugium, or a dedicated area for compatible supplementary filtration.
• Independent extension use: The extension can instead be disconnected and configured as an RO/DI freshwater reservoir, saltwater reservoir for water changes, or separately equipped coral frag tank.
• Configuration affects operating volume: When the extension is used independently as a reservoir or frag tank, its water does not form part of the aquarium's circulating filtration volume.
• Adjustable skimmer chamber: The main sump's operating water depth can be set between 21 and 27 cm (8.3-10.6 inches), accommodating compatible protein skimmers designed for this deeper working range.
• Optional dedicated refugium divider: A compatible partition provides another option for establishing a refugium section within the main sump.
• Filtration planning: Decide whether the extension will be connected or independent before choosing equipment, plumbing arrangements, freshwater storage, and automated water-change accessories.

ReefMat-Ready Mechanical Filtration

The REEFER S-850 G3+ includes a removable mechanical filtration compartment in its main sump. The supplied filter bags and media cups provide conventional debris collection, while the compartment can be converted for compatible automatic fleece filtration when the aquarist prefers reduced manual filter maintenance.

• Two 225-micron filter bags: The supplied fine-mesh filters capture suspended particles and detritus entering from the overflow and can be removed for cleaning.
• Two filter media cups: The mechanical section includes cups that provide alternative filtration arrangements to the supplied bags.
• Removable ReefMat-ready compartment: The mechanical filter assembly can be removed to accommodate compatible automated roller filtration without rebuilding the standard drain plumbing.
• Optional ReefMat 1200: Red Sea specifies the ReefMat 1200 for the equivalent REEFER-S MAX 850 G3+ configuration, providing a manufacturer-listed automatic filtration upgrade.
• Adjustable protein skimming: The main sump's 21-27 cm (8.3-10.6 inch) operating range should be matched to the selected skimmer's recommended depth.
• Combined filtration flexibility: Automatic mechanical filtration can be paired with a connected extension refugium or other compatible filtration equipment according to the intended nutrient-management strategy.

Dual 32 mm Returns and ReefGate Precision Plumbing

The S-850 G3+ uses Red Sea's larger-format return plumbing, with an enlarged central overflow, hydrodynamically optimized pipework, and two curved 32 mm outlets for distributing filtered water back into the display. The ReefGate valve provides fine control over drainage to help maintain quiet operation.

• Two curved 32 mm (approximately 1.26 inch) return outlets: The dual connections can be supplied by a compatible single return-pump arrangement or two separate pumps, depending on the selected equipment and plumbing.
• High-precision ReefGate valve: Small adjustments regulate the main downflow, allowing the operating water level inside the overflow to be balanced against the return pumps.
• Enlarged rectangular downflow: The redesigned inlet helps reduce turbulence as aquarium water enters the drain.
• Removable surface-skimming combs: The central overflow collects water through accessible comb sections that can be cleaned to prevent deposits from restricting flow.
• Hydrodynamically optimized pipework: Factory-designed piping helps reduce unnecessary flow resistance between the aquarium and sump.
• Correct plumbing size: The S-850 G3+ uses dual 32 mm outlets, unlike the 25 mm connections on the smaller S-550 and S-700 G3+ models. Custom plumbing must be matched to the 32 mm specification.
• Return flow versus reef circulation: The sump returns handle water exchange through filtration, while independently selected wavemakers provide the additional in-tank movement needed around large rock structures and coral colonies.

ReefControl Pro and Integrated Automatic Top-Off

ReefControl Pro and the ReefControl ATO Module are standard equipment on the S-850 G3+. Together, they provide digital freshwater top-off and temperature monitoring, with connections available for additional compatible ReefSense probes and controlled devices.

• ReefControl Pro Controller: Supports up to seven compatible ReefSense digital probes or sensors and two 12V DC devices, providing expansion capacity for a larger aquarium installation.
• Automatic freshwater replenishment: The ReefControl ATO Module uses a digital water-level sensor and dedicated DC pump to replace water lost through evaporation.
• Integrated temperature monitoring: The ATO level sensor incorporates a digital thermometer, providing readings and available notifications through the ReefControl system.
• ATO installation hardware: The module includes its sensor, mounting bracket, DC pump, silicone tubing, tube holder, and siphon breaker.
• ReefBeat integration: Compatible equipment and sensor readings can be accessed through Red Sea's connected monitoring ecosystem.
• Optional ReefSense expansion: Additional compatible pH, salinity, ORP, and other monitoring probes can be purchased separately as required.
• Optional AC device control: Compatible ReefControl Power hardware provides additional equipment-management options through ReefBeat.
• Base-system distinction: ReefControl Pro and the ATO Module are included. Additional water-parameter probes and the lighting, pumps, skimmer, and roller filter associated with the MAX package are separate purchases.

Equipment Planning for a Six-Foot REEFER-S Aquarium

The S-850 G3+ is intended for substantial marine fish displays, LPS or soft coral reefs, and appropriately equipped mixed reefs. Its long display and split-sump arrangement require careful planning of lighting, return circulation, skimming, water movement, and equipment access before filling.

• Return pump reference: Red Sea specifies two ReefRun G2 12000 pumps in the corresponding REEFER-S MAX 850 G3+ configuration. Return pumps are sold separately with this standard reef-ready system.
• Reef lighting reference: The MAX version uses three ReefLED G2 170 fixtures. Alternative lighting should provide suitable coverage and intensity across the 180 x 68 cm (70.9 x 26.8 inch) footprint.
• Protein skimmer reference: Red Sea pairs the MAX package with an RSK DC 900. Other skimmers must fit the sump and operate within its adjustable 21-27 cm (8.3-10.6 inch) water-depth range.
• Supplementary circulation: The corresponding MAX system uses two ReefWave 45 pumps. Independently selected wavemakers can provide flow behind rockwork and across coral colonies beyond the sump return.
• Automatic filtration: The ReefMat 1200 is an optional upgrade for customers who prefer automatic removal of suspended debris.
• Freshwater storage: The included ATO system requires a freshwater supply. The extension sump may be configured as an independent RO/DI reservoir if that arrangement suits the installation.
• Compared with the S-700: The S-850 adds 30 cm (11.8 inches) of display length, the multipurpose extension sump, and larger dual 32 mm return connections.
• Compared with the S-1000: The S-850 shares the premium cabinet, 68 cm depth, 65 cm height, and split-sump architecture of the S-1000 in a shorter 180 cm installation.

Red Sea Reefer S-850 G3+ Black Specifications

• Total published system volume: 850 L / approximately 224.5 US gal.
• Display aquarium volume: 680 L / approximately 179.6 US gal.
• Combined main and extension sump volume: 170 L / approximately 44.9 US gal.
• Display dimensions: 180 cm L x 68 cm W x 65 cm H / approximately 70.9 x 26.8 x 25.6 inches.
• Total height with cabinet: 153 cm / approximately 60.2 inches.
• Ultra-clear front glass thickness: 19 mm / approximately 0.75 inches.
• Glass construction: Eurobraced ultra-clear glass with additional bottom reinforcement and high-quality euro-silicone bonding.
• Cabinet: Black marine-spec anodized aluminum superstructure with replaceable panels and hidden adjustable leveling feet.
• Cabinet equipment features: Slide-out control panel and auxiliary equipment compartment.
• Return outlets: Two curved 32 mm connections for compatible single- or dual-pump arrangements.
• Filtration: Split REEF-SPEC sump with professional main sump and multipurpose glass extension sump.
• Mechanical filtration: Removable ReefMat-ready compartment with two 225-micron filter bags and two media cups.
• Skimmer chamber water depth: Adjustable 21-27 cm / approximately 8.3-10.6 inches.
• Refugium compatibility: Optional main-sump divider or connected extension-sump refugium configuration.
• Included controller: ReefControl Pro, supporting up to seven compatible ReefSense probes or sensors and two 12V DC devices.
• Included automatic top-off: ReefControl ATO Module with digital level and temperature sensor, DC pump, and installation accessories.
• MAX-package return pump reference: Two ReefRun G2 12000 pumps, sold separately.
• Optional automatic filtration: ReefMat 1200, sold separately.
• Manufacturer warranty: Standard 3 years, extendable to 5 years with registration within 90 days of purchase at no additional charge, subject to warranty terms.

Red Sea REEFER G3+ Series Video

Shipping Notes

• Red Sea aquariums are exempt from our free shipping policy.
• To avoid delays, please order your aquarium separately from other products. If purchasing additional items, place one order for the aquarium and a second order for your other products.
• Orders shipping to the Northwest Territories, Yukon, or Nunavut require a shipping quote. Please call for details.
• Red Sea aquariums are brought in and shipped on an as-ordered basis. The average turnaround time before shipping is approximately two business days, except where noted below.
• All shipments outside the Vancouver area are sent by trucking company with fully insured residential delivery and power tailgate service.
• Orders within British Columbia and, in some circumstances, Alberta may require an additional 5-10 business days for processing. Orders from Alberta and provinces farther east generally ship directly from the distributor in Ontario within two business days.
• For in-store pickup, select that option at checkout to avoid delivery charges. You will be notified when the aquarium arrives, usually within 5-10 business days.
• Red Sea MAX S Series aquariums are always special order and generally require 3-6 weeks before shipping.
• Freight delivery includes transporting the aquarium to the destination address and unloading it. The freight company is not responsible for carrying the aquarium inside the building.
• Freight charges have been substantially subsidized to help reduce the delivery cost of your new Red Sea aquarium.
• Rural, remote, and extended-service areas may require an additional shipping charge. We will contact you before shipping if an adjustment is necessary.

Directions

• Confirm the installation area can support the weight of the aquarium, cabinet, water, rockwork, and equipment. Check delivery access, floor structure, and required service clearances before assembly.
• Assemble and level the anodized aluminum cabinet according to Red Sea's instructions, then arrange suitable lifting assistance to position the large eurobraced aquarium.
• Install the main sump, glass extension sump, ReefGate valve, overflow, and supplied return plumbing. Decide whether the extension will be connected or independently operated before completing the setup.
• Install ReefControl Pro and the ReefControl ATO Module, including the digital level and temperature sensor, top-off pump, tubing, and siphon breaker according to the manufacturer's instructions.
• Arrange compatible electronic equipment on the slide-out control panel, allowing safe cable routing and access for servicing.
• Install the selected return pumps, skimmer, lighting, heating, and circulation equipment. Set the skimmer chamber water level to the requirements of the selected skimmer.
• Follow Red Sea's initial-fill and leak-inspection procedure, then adjust the ReefGate in small increments, allowing the overflow level to stabilize between changes.
• Perform a power-out test to confirm that the connected filtration system can accommodate drain-back water when the return pumps stop.
• Clean the mechanical filters, surface-skimming combs, and ATO sensor regularly. If the extension is used independently, maintain its water quality and equipment according to its intended application.
• Register the aquarium with Red Sea within 90 days of purchase to qualify for the extended warranty.

What's Included

• REEFER S-850 G3+ eurobraced ultra-clear glass aquarium with additional bottom bracing
• Black marine-spec anodized aluminum cabinet superstructure with replaceable exterior panels and hidden adjustable leveling feet
• Slide-out equipment control panel
• Professional REEF-SPEC main sump with adjustable-height skimmer chamber and removable ReefMat-ready mechanical filtration compartment
• Multipurpose glass extension sump for connected or independent configurations
• Two 225-micron mechanical filter bags
• Two filter media cups
• Downflow and dual return plumbing with ReefGate precision valve
• Central overflow with removable surface-skimming combs
• Two curved 32 mm return outlets
• ReefControl Pro Controller
• ReefControl ATO Module with digital level and temperature sensor, DC top-off pump, and installation accessories