Red Sea Reefer 425 G3 - Black Cabinet

The Red Sea Reefer 425 G3 - Black Cabinet is a premium 433 litre / 114.4 gallon reef-ready aquarium and cabinet system for aquarists who want a larger 120 cm euro-braced REEFER G3 display with a black marine-spec cabinet and Red Sea’s upgraded sump-based infrastructure.

As the first classic REEFER G3 size in the euro-braced range, the 425 G3 combines a substantial ultra-clear glass display with a REEF-SPEC sump, ReefMat-ready mechanical chamber, ReefGate precision valve, central overflow with removable surface skimmer, curved dual return nozzles, pre-assembled plumbing, and integrated ReefATO+ smart top-off control. This base system is built for customers who want a professional tank, cabinet, sump, and plumbing foundation while selecting lighting, return pump, skimmer, heating, flow, and automation hardware separately.

Red Sea REEFER 425 G3 Black Reef System

• Large classic REEFER platform: The 425 G3 moves into a 433 L total system volume, giving reef keepers more stability, display presence, and room for coral growth than smaller REEFER models.
• Euro-braced display: The 425 is part of the G3 euro-braced range for added structural strength and long-term durability.
• 120 cm by 60 cm reef canvas: The display gives both length and depth for more natural aquascapes, larger coral zones, and better fish movement.
• Black cabinet finish: The black marine-spec cabinet gives the aquarium a bold modern look and visually frames the reef display.
• Base-system flexibility: Return pump, skimmer, lighting, heater, wavemakers, dosing equipment, and optional automation are chosen separately to match the intended reef build.
• Strong upgrade platform: The included sump, ReefATO+, and ReefMat-ready layout create a serious base for a high-performance reef aquarium.

Euro-Braced Ultra-Clear Display

• 343 litre display volume: The 90.6 gallon display gives significant room for coral colonies, aquascaping, and suitable reef fish.
• 120 x 60 x 55 cm dimensions: The 60 cm depth creates a more three-dimensional reefscape than narrower 120 cm aquariums.
• Euro-braced construction: The bracing adds strength while preserving a clean, premium top profile for a larger display.
• Mixed glass thickness: The 425 G3 is listed with 12 mm front glass, 15 mm side glass, 12 mm bottom glass, and 12 mm back glass.
• Ultra-clear glass: Low-iron viewing panels help improve clarity, coral colour visibility, and overall display impact.
• Cabinet-contained equipment: The sump keeps core filtration and support gear below the aquarium instead of crowding the display.

G3 Flow System for a Larger Display

• Hydrodynamically optimized plumbing: The REEFER G3 flow system is designed for more efficient circulation and improved water movement.
• Quiet rectangular downflow: The enlarged inlet reduces turbulence and helps make drain tuning quieter.
• ReefGate precision valve: The high-precision downflow valve gives fine control for stable, near-silent operation.
• Central overflow: The removable surface skimmer helps pull surface film into the filtration system for better water clarity.
• Curved dual returns: Improved return outlets help spread water into the wider 120 cm display.
• Pre-assembled plumbing: Included downflow and return parts simplify installation and help maintain a clean factory-designed layout.

Large REEF-SPEC Sump and ReefATO+ Control

• 90 litre sump volume: The larger sump provides generous space for mechanical filtration, skimmer selection, return equipment, reactors, media, dosing lines, and probes.
• ReefMat-ready mechanical section: The sump includes micron socks and media cups and is designed for optional Red Sea ReefMat installation.
• Integrated ReefATO+: ReefATO+ helps stabilize water level and salinity while providing temperature monitoring and leak detection.
• Flexible filtration planning: The sump supports a wide range of equipment layouts for mixed reef, LPS, soft coral, and more advanced coral systems.
• Service-friendly cabinet space: The under-tank sump layout makes maintenance, filter changes, skimmer cleaning, and equipment upgrades more practical.
• Red Sea ecosystem compatible: The system pairs well with optional ReefRun pumps, ReefLED lighting, ReefMat, ReefWave, ReefDose, REEFER skimmers, and ReefBeat-connected devices.

Red Sea Reefer 425 G3 Black Specifications

• Total system volume: 433 L / 114.4 gal.
• Display volume: 343 L / 90.6 gal.
• Sump volume: 90 L / 23.8 gal.
• Display dimensions: 120 cm L x 60 cm W x 55 cm H / approx. 47.2 x 23.6 x 21.7 in.
• Total height with cabinet: 142 cm / approx. 55.9 in.
• Glass thickness: 12 mm front glass, 15 mm side glass, 12 mm bottom glass, 12 mm back glass.
• Display format: Euro-braced ultra-clear glass aquarium.
• Cabinet: Black marine-spec plywood cabinet with leveling feet.
• Filtration: REEF-SPEC sump with mechanical chamber, micron socks, media cups, ReefMat-ready layout, and ReefATO+.
• Recommended return pump: Red Sea ReefRun G2 6000, sold separately.
• Recommended lighting: 2 x Red Sea ReefLED G2 170, sold separately.
• Recommended ReefMat: Red Sea ReefMat 500, sold separately.

Application Notes for the REEFER 425 G3

• Best use: Ideal for larger mixed reefs, LPS displays, soft coral aquariums, and custom coral systems needing more depth and water volume.
• Lighting planning: The recommended lighting is sold separately and should be selected for full coverage across the 120 cm by 60 cm footprint.
• Return pump planning: The recommended ReefRun G2 6000 is sold separately and should be matched to desired sump turnover.
• Flow planning: Additional wavemakers are recommended for reef circulation beyond the return outlets, especially in coral-heavy aquascapes.
• ReefMat upgrade path: The ReefMat-ready sump supports automatic fleece-roll filtration with an optional ReefMat.
• Not included: Lighting, return pump, protein skimmer, heater, wavemakers, livestock, rock, sand, salt, optional ReefMat, dosing equipment, and test kits are sold separately unless otherwise stated.

Red Sea REEFER G3 Series Video

Setup and Installation Notes

• Assemble and level the cabinet: Build the black cabinet according to Red Sea’s instructions and confirm it is level before placing the aquarium.
• Plan heavy equipment before filling: Choose return pump, skimmer, lighting, heater, wavemakers, and any optional automation before starting the reef.
• Install plumbing carefully: Confirm the overflow, downflow, ReefGate valve, return plumbing, sump, and ReefATO+ are installed correctly.
• Leak test first: Fill and run the system with freshwater before final saltwater setup to verify plumbing and sump operation.
• Tune the ReefGate gradually: Adjust the drain valve slowly until the overflow and sump run quietly.
• Use RO/DI water: RO/DI water is recommended for salt mixing and top-off.
• Cycle before stocking: Establish biological filtration before adding fish or corals, then stock the system gradually.

What’s Included

• Euro-braced ultra-clear glass aquarium
• Black marine-spec plywood cabinet with leveling feet
• REEF-SPEC sump with 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.