Red Sea REEFER 350 G3 — Rimless 90.3 gal Reef Aquarium on a 47 in Footprint

The REEFER 350 G3 is our best-selling Red Sea system, and its spot in the lineup explains a lot: a 47.2 in (120 cm) viewing pane, 90.3 gal (342 L) of total volume, and it is the last rimless model as you move up the series — from the 425 onward, Red Sea switches to Euro-brace construction. If you want the big saltwater display with nothing framing the glass, this is where the road ends.

What Red Sea publishes for this model

• Total system water volume: 342 L (90.3 gal US)
• Display tank volume: 273 L (72.1 gal US)
• In-cabinet sump volume: 69 L (18.2 gal US)
• Display tank (L × W × H): 120 × 50 × 53 cm (47.2 × 19.7 × 20.9 in)
• Total system height: 140 cm (55.1 in), excluding the light unit
• Ultra-clear glass: front 12 mm (0.5 in) · sides 15 mm (0.6 in) · bottom 12 mm (0.5 in) · back 12 mm (0.5 in)
• Rim type: rimless, beveled edges, no bracing
• Cabinet: marine-spec plywood with leveling feet, white or black

Every number above comes from Red Sea's published spec table and its MyREEFER configurator, both re-read while building this page.

Choosing between the 350 and the 425

Both share the same 120 cm frontage and the same cabinet height. What separates them is depth and structure: the REEFER 425 G3 adds 10 cm of depth (60 cm instead of 50) and 91 L of volume, but does it with a Euro-brace ring around the top of the tank. The 350 keeps a fully open top with no frame in your line of sight. Going the other way, if the budget is tighter, the REEFER 250 G3 keeps the rimless formula on a 90 cm footprint.

Weight, flooring and clearances

Red Sea rates the complete system in operation at 530 kg (1,170 lb) over a 120 cm footprint, and the series manual asks you to confirm the floor under the system is rated for that load before setup. The empty glass tank alone weighs 64 kg (140 lb) — plan for enough people to lift it onto the cabinet safely.

Leave at least 10 cm (4 in) behind the tank for cables and airflow, and about 60 cm (24 in) clear on one side to reach the back. The cabinet top sits roughly 86 cm (34 in) off the floor. Red Sea recommends a stable room around 22°C (72°F), away from direct sun and HVAC vents.

The ReefATO+ top-off system, included with the tank

Every REEFER G3 ships with the ReefATO+: a level sensor in the pump chamber, temperature probe and leak detection, all connected to the ReefBeat app. It replaces evaporated water automatically and keeps salinity steady between visits. Here is how it installs, filmed at our shop.

What the ReefATO+ does not include: the reservoir. The series manual states it plainly — REEFER G3 systems ship without a container for top-off water. A jug in the cabinet works, but a ReefCan uses the equipment space better and refills without taking anything apart.

The setup Red Sea sizes for a 350

In its official configurator, this is what the manufacturer identifies as the right sizing for this volume — not our suggestion, their own answer:

• 2 × ReefLED G2 115 — two units, because a 47 in pane will not light evenly under a single fixture
• 2 × ReefWave 25 pumps in opposition for circulation
• 1 × ReefRun G2 6000 (3,600–6,500 L/h · 950–1,700 gph) as the return pump — also the model the series manual recommends for the 350
• 1 × RSK 600 DC, the size Red Sea flags as best for an SPS reef at this volume
• 1 × ReefMat 500 in place of filter socks

Nothing forces you to buy it all at once or stay within one brand. But when someone asks what size gear a 350 needs, that list is the manufacturer's own answer.

Downflow, sump and routine maintenance

Surface water passes the removable combs of the surface skimmer into the overflow box, then drops through a flow-regulated main downpipe backed by a secondary bypass pipe. The precision gate valve on the main downpipe holds the overflow water level between the two intakes: set correctly, it removes the noise of water flowing down to the sump — if you can hear it, it needs adjusting. Here is Red Sea's own walkthrough of that valve.

Down in the sump, water runs through the mechanical stage — 225 micron filter bags or media cups, your choice, with at least three sets of bags in rotation recommended. To move to a ReefMat, you pull the filter-bag tray and the removable divider wall without replacing the sump. A bubble-trap labyrinth with a coarse sponge protects the pump chamber, and that constant-level chamber is where the ReefATO+ takes its reading.

Independent reviews

Two independent looks at this exact tank from the Aquarium Butler channel — a first review at setup, then an update after four months of running it:

Our advice

The REEFER 350 is our biggest seller, and it is not our biggest seller for nothing. It is the right pick when you want room for a real variety of fish while staying reasonable on budget. It will make you happy — and your family too.

This is a beautiful family hobby: you gather around the aquarium, spend good time together, come by the shop to pick fish as a family. These are the things that bring kids closer to nature, and it is a wonderful education for them — a great pastime that brings everyone together at home.

— Stéphane, Aquarium ReefSolution

Build the project at your own pace

Nobody buys a complete reef in one order, and that is perfectly normal. Write to us or stop by the shop in Laval with your plan and your budget: we will build the configuration together, putting first what needs to be there from day one. It is part of the service, and it costs nothing.

Warranty

The base warranty is 3 years worldwide. Canada is among the countries where registering the system within 90 days of purchase extends coverage to 5 years at no charge. It covers the glass aquarium and the cabinet, applies to the original owner only, and requires proof of purchase. Devices supplied with the system, including the ReefATO+, carry their own warranty.

Why buy from ReefSolution

• Official Red Sea retailer: warranty handled with direct manufacturer support
• Store in Laval, QC: REEFER systems assembled and running, to see before you buy
• Delivery across Canada. Free shipping available depending on order total.
• Real after-sales service, in both languages, from people who run reef tanks at home
• An RO/DI unit to make your own water, and a net cover if jumpy species are on your stocking list for an open-top tank

Frequently asked questions

How many gallons is the Red Sea REEFER 350 G3?

342 L total, which is 90.3 US gallons per Red Sea's official configurator. The display tank alone holds 273 L (72.1 gal US) and the sump 69 L (18.2 gal US).

What are the exact dimensions of the REEFER 350 G3?

The display tank measures 120 × 50 × 53 cm (47.2 × 19.7 × 20.9 in). With the cabinet, the system stands 140 cm (55.1 in) tall, excluding the light unit.

What return pump does a REEFER 350 G3 need?

The series manual recommends one ReefRun G2 6000 (3,600–6,500 L/h · 950–1,700 gph), and the MyREEFER configurator selects the same model for this tank. The return pump is not included with the system.

How much does a full REEFER 350 G3 weigh?

Red Sea rates the complete running system at 530 kg (1,170 lb) over a 120 cm footprint, and the manual asks you to confirm floor capacity before setup. The empty glass tank weighs 64 kg (140 lb).

Is the REEFER 350 G3 rimless?

Yes — and it is the largest rimless model in the series. From the 425 up, Red Sea moves to Euro-brace construction. The 350 pairs the 47 in pane with a fully open, frameless top.

How many lights do I need on a REEFER 350 G3?

Red Sea specifies two ReefLED G2 115 units for this model, both in its spec table and in its configurator. A single fixture leaves the ends of a 47 in tank under-lit.