Red Sea REEFER 525 G3 — 142.7 gal Reef Aquarium on a 59 in Cabinet with ReefATO+

Red Sea REEFER 525 G3 — the 59-inch reef platform

The REEFER 525 G3 is the 142.7 gal US (540 L) system of Red Sea's third generation: a 59 in (150 cm) Euro-braced tank in 15 mm ultra-clear glass, a 30.6 gal US (116 L) REEF-SPEC sump that is ReefMat-ready out of the box, and the ReefATO+ auto top-off module included. It replaces the REEFER XL 525 of the G2+ generation — and it happens to be the reef tank we run ourselves at the store.

Red Sea's official introduction to the G3 series:

Official manufacturer specifications

• Total system water volume: 142.7 gal US (540 L)
• Display tank volume: 111.7 gal US (423 L)
• In-cabinet sump volume: 30.6 gal US (116 L)
• Display tank dimensions: 59 × 23.6 × 21.7 in (150 × 60 × 55 cm), height excluding light
• Total system height: 55.9 in (142 cm)
• Ultra-clear glass: 15 mm on the front, sides, bottom and back panels
• Rim type: Euro brace
• Cabinet top height: 34 in (86 cm) from the floor, per the series manual
• Manufacturer-stated full system weight: 1875 lb (850 kg)
• Glass aquarium weight alone: 275 lb (125 kg)

Weight, clearances and placement

The series manual calls for flooring rated to hold 1875 lb (850 kg) once the saltwater aquarium is running. Leave at least 4 in (10 cm) behind the cabinet for cables and chiller airflow, and 24 in (60 cm) between one side and the nearest wall for rear access. Red Sea recommends a stable room at 72 °F (22 °C), away from AC vents, heaters and direct sunlight. The glass tank alone weighs 275 lb (125 kg) — plan enough people to lift it onto the cabinet.

What sets the 525 G3 apart

The 525 is the entry point to the 59 in footprint in the straight REEFER line: enough length for a mature SPS reefscape in distinct zones without moving up to the 625's width and height. The G3 generation gives it 15 mm glass on every panel, hydrodynamic piping with a high-precision gate valve for quiet-running downflow, and a fortified plywood cabinet with a dedicated chiller and hardware chamber — a feature of the larger models in the series.

In the box — and what is not

Included: the ultra-clear glass tank, the cabinet, the ReefMat-ready REEF-SPEC glass sump with optional refugium divider, the internal piping kit with return nozzle, and the complete ReefBeat-connected ReefATO+ system.

Not included: lighting, return pump, protein skimmer, ReefMat, wave pumps — and the top-off reservoir: the series manual states plainly that REEFER G3 systems do not include a reservoir for the top-off water.

Red Sea's published MAX configuration for this model: ReefLED G2 lighting (3 × 115 or 2 × 170 units), a ReefRun G2 8000 return pump (1080–2200 gph / 4100–8300 L/h) named for the 525 in the series manual, an RSK 600 DC skimmer — the "Best size for SPS" pick in the MyREEFER configurator —, a ReefMat 1200 roller filter and two ReefWave 45 gyre pumps.

Plan for these as well

Since no top-off reservoir ships with any G3, a ReefCan slides into the cabinet to feed the ReefATO+. To produce RO water for a 142.7 gal system, an RO/DI unit such as the AquaticLife Classic 100 GPD covers the need. And because this is an open-top reef tank, a Red Sea net cover protects jumping species.

The REEF-SPEC sump, in detail

Water travels down the silent dual-intake downflow into a compact reception chamber, through the 225-micron filter bags, then into the constant-height skimmer chamber. A bubble-trap labyrinth with a coarse sponge guards the return pump compartment, where the ReefATO+ sensor holds a steady level. Installing a ReefMat only takes removing the filter-bag tray and the removable divider — no modification needed. The optional refugium wall splits the main chamber in two for hobbyists growing macroalgae and microfauna.

Our advice

"The 525 G3 is the model we picked for our own home — Myma and me. I went back and forth between the 425 and the 525, but the 525 won my heart; the 625 was a bit more budget than we wanted. The 525 satisfies me one hundred percent. Of all the aquariums I have owned, it is the quietest — you do not hear it at all; compared to our old MAX Nano XXL, it is night and day — and the finish is impeccable, like every Red Sea. With five feet of length and real depth, I can keep the fish I want: I treated myself to tangs, which I love. We installed the ReefATO+ for peace of mind: it draws from a reservoir our RO/DI unit refills automatically — the level takes care of itself. That said, be realistic: this is a big tank, it is heavy, it takes space and manpower. We lifted the tank onto the cabinet with two people, a friend and me, once the cabinet was built. If this is your first tank this size, you need a solid floor — it is an investment, but everyone who visits is blown away by the aquarium. We have had it for a good while now and our opinion has not changed. Like all Red Sea aquariums, shipping is a flat $100 rate anywhere in Canada, and you have our support at all times to help you."

— Stéphane, Aquarium ReefSolution

5-year warranty in Canada

REEFER G3 systems carry a 3-year warranty, and the original purchaser can extend it to 5 years at no charge by registering the system with Red Sea within 90 days of purchase — Canada is one of the eligible markets. The extension covers the structural integrity of the glass tank and cabinet.

Why buy from ReefSolution

We are an authorized Red Sea dealer with a store in Laval, Québec, and we run the gear we sell — starting with this very tank. Secure shipping across Canada. Considering a 47 in footprint instead? Have a look at the REEFER 350 G3.

FAQ — Red Sea REEFER 525 G3

What comes with the REEFER 525 G3?

The 15 mm ultra-clear glass tank, the cabinet, the ReefMat-ready REEF-SPEC sump, the internal piping kit and the ReefATO+ auto top-off system. Lighting, return pump, skimmer and flow pumps are chosen separately.

What return pump does the REEFER 525 G3 need?

The series manual recommends one ReefRun G2 8000 (1080–2200 gph / 4100–8300 L/h) for this model — the same pump running on our own 525 G3.

Is a top-off reservoir included?

No. The series manual states that REEFER G3 systems do not include a reservoir for the top-off water. Red Sea's ReefCan is built for that exact job and fits inside the cabinet.

How much does a full REEFER 525 G3 weigh?

Red Sea states 1875 lb (850 kg) for the complete system filled with water. Check your floor rating before setup — the glass tank alone weighs 275 lb (125 kg).