Red Sea Reefer 300 G3 Aquarium System

• REEFER 300 G3 Aquarium
• Marine-Spec Cabinet (in your selected color)
• Glass Sump & Pre-Glued Plumbing
• ReefATO+ Auto Top Off System
• 5 Year Manufacturer Warranty
• (3 years standard + 2 upon registration)
• All REEFER G3 aquariums include a standard 3-year warranty.
• Register your brand-new Red Sea system
• within 90 days of the original date of purchase to add 2 years of protection at no extra cost. Please see Red Sea's website for full terms & conditions.

Red Sea has been building aquariums for years, delivering high-quality, thoughtfully engineered systems that make reefing easier and more enjoyable. The REEFER G3 series is a top choice for hobbyists who want a premium rimless aquarium with the flexibility to choose their own filtration, lighting, and equipment. Each system offers a strong, reef-ready foundation with smart features and a clean, modern design.

The REEFER 300 G3 Aquarium

Red Sea’s REEFER G3 aquariums use ultra-clear, beveled-edge glass for vibrant, distortion-free viewing. A low-profile black overflow box and hidden plumbing keep the display clean and uncluttered, while the rimless design offers a sleek, modern look that lets your aquascape shine.

Display Tank Dimensions: 89.9 cm x 57.4 cm x 55.1 cm

REEFER Marine-Spec Cabinet

The marine-spec laminated cabinet is made of plywood and precisely follows the contour of the aquarium for a seamless fit. It’s built for strength and moisture resistance, with leveling feet and stainless steel hinges to ensure long-term durability. Stands are available in black or white finishes to complement any space. Reinforced aluminum supports are included for the REEFER 525 models and larger.

Reef-Ready Sump

The included glass sump features a clean, straightforward layout that makes it easy to set up and maintain. Its flexible design is compatible with a wide range of filtration equipment, including Red Sea’s ReefMat fleece roller filters and REEFER DC protein skimmers, giving you plenty of upgrade options as your system grows (ReefMat and REEFER Protein Skimmer are sold separately).

Ready-to-Use Plumbing

REEFER G3 systems include all the plumbing you need, ready for quick assembly with no gluing required. The redesigned G3 layout reduces the number of 90-degree turns for smoother flow, while the new ReefGate flow valve makes it easy to fine-tune your system's drain plumbing so that it runs quietly.

Each REEFER G3 system includes the ReefATO+, combining top off control, temperature monitoring, and leak detection all in one device connected to the ReefBeat App.

Automatic Top Off:

The ReefATO+ sensor features a built-in backup sensor 2.5 cm above the primary sensors to automatically shut down the ATO pump in the event of an overfill. With multiple probes built onto the sensor, an indication of actual water level can always be seen on the ReefBeat App.

Temperature Monitoring:

The temperature sensor integrated in the ATO+ sensor has been pre-calibrated to give an accuracy of ±0.1°. If the temperature goes outside the acceptable range, you will be sent a ReefBeat notification.

Leak Detection:

The highly sensitive, Reef-Spec leak detector (with saltwater resistant titanium probes) detects both saltwater and RO/DI water. If a leak is detected, the ATO pump is immediately disabled, and after a few seconds to confirm that the leak persists, the controller sounds an optional audible alarm and sends a notification.

• ReefMat 500 Fleece Roller Filter
• REEFER DC 300 Protein Skimmer