Red Sea REEFER 250 G3 — Rimless 65 gal Reef Aquarium on a 35.4 in Footprint

The REEFER 250 G3 sits at a very deliberate point in Red Sea's line-up: a 90 cm (35.4 in) front pane, 245 L of total volume, and enough length for fish to actually swim rather than circle. It is the size that settles the argument between the project you want and the space you really have.

What Red Sea publishes for this model

• Total system water volume: 245 L (65 US gal)
• Display tank volume: 203 L (53.6 US gal)
• Sump volume: 42 L (11.1 US gal)
• Display tank (L × W × H): 90 × 50 × 53 cm (35.4 × 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 12 mm (0.5 in) · bottom 12 mm (0.5 in) · back 10 mm (0.4 in)
• Rim type: rimless, no internal brace, bevelled edges
• Cabinet: marine-grade plywood on adjustable feet, white or black

Two corrections against figures circulating elsewhere: the tank is 90 cm long, not 100, and the display volume is 203 L. Everything above comes from the specification table published by the manufacturer and from its MyREEFER tool, both read while this page was being built.

How the 250 differs from the 200

Both share a cabinet height, a 42 L sump and the same recommended return pump. Geometry is what separates them: the REEFER 200 G3 is a deep 60 cm square, while the 250 stretches to 90 cm across at only 50 cm deep. For a similar volume the 250 gives a more panoramic view, an easier aquascape to compose, and a genuine swimming lane. That geometry is also why Red Sea specifies two light units on the 250 against one on the 200.

Weight, floors and clearances

Red Sea rates the running system at 380 kg (838 lb) spread over a 90 cm footprint. The empty tank on its own weighs 55 kg (121 lb): a two-person lift at minimum, and both of them need to be able to finish the carry.

Allow at least 10 cm (3.9 in) between wall and tank for cabling and airflow, plus roughly 60 cm (23.6 in) clear on each side so you can reach behind when work is needed. The cabinet top lands about 86 cm (33.9 in) above the floor. Red Sea suggests holding the room near 22 °C (71.6 °F), away from direct sunlight and air-conditioning vents.

The ReefATO+ comes with the tank

Every REEFER G3 ships with the ReefATO+: level sensor, temperature probe and leak detector, all reporting to the ReefBeat app. It replaces evaporated water and stops salinity from creeping up between visits. Here is the install, filmed at our store.

What the ReefATO+ does not bring: the reservoir. REEFER G3 systems ship without any top-off water container — the series manual states it outright. So it needs a source: a jug in the cabinet works, while a ReefCan 18 or 40 uses the available space better and refills without dismantling half the stand.

The build Red Sea itself puts on a 250

The factory-assembled REEFER MAX 250 G3 contains exactly this — the manufacturer's own sizing for this volume, not a shop suggestion:

• 2 × ReefLED G2 115 — two units, because 90 cm of front glass does not light evenly from one
• 2 × ReefWave 25 (7,500 L/h · 1,981 gph each), mounted opposing
• 1 × ReefRun G2 4000 (2,000–4,000 L/h · 530–1,060 gph) as the return pump
• 1 × RSK 300 DC (water 1,000 L/h · 264 gph, air 500 L/h · 132 gph)
• 1 × ReefMat 250 in place of the filter sock drawer

No obligation to buy it all at once, and none to stay inside one brand. But when someone asks what size they need, that list is the manufacturer's answer.

Two independent owner videos

These two come from an independent hobbyist channel, not from Red Sea and not from us — an unboxing and build, then a full update two months in on the same tank. They are the closest thing to seeing the system in a real home before you buy one.

Downflow, sump and routine upkeep

Surface water leaves through removable combs into the overflow chamber, then drops through a main pipe metered by the ReefGate, the high-precision valve fitted as standard on G3 systems. A second pipe serves as the safety line. Dialled in, the downflow runs very quietly; left rough, it sings. Red Sea also widened the pipe inlet into a rectangle, which breaks up the turbulence that causes the noise, and claims up to 50% more circulation on the G3 generation thanks to the new pipework.

Below, water passes the mechanical filtration module — 225 micron socks or media cups. Red Sea suggests three sets of socks in rotation, which keeps washing off the critical path. The whole module pulls out to accept a ReefMat with no sump modification. A baffle and sponge trap bubbles ahead of the return pump, and it is that constant-level chamber the ReefATO+ measures.

Our advice

The REEFER 250 is a strong seller, and it is not a strong seller by accident. It is the right compromise: enough room to keep a wider variety of fish while staying reasonable on budget. These tanks are easy to handle, they do not eat the room, and the weight stays manageable — it works on most floors.

Then there is the side of it people talk about less. This is a beautiful family hobby. Everyone gathers around the tank, you spend good time together, you come down to the store and pick fish as a family. Those are the things that bring children closer to nature, and it is a wonderful education for them. A tank like this one will make you and your family happy — it is a fine way to bring everybody together at home.

— Stéphane, Aquarium ReefSolution

Building the project at your own pace

Nobody buys a complete reef in a single order, and that is entirely normal. Write to us or come to the Laval store with your project and your budget: we set out the configuration that suits you, prioritising what has to be there on day one and letting the rest follow later. It is part of the service, and it costs nothing.

Warranty

Base coverage runs 3 years worldwide. Canada is among the countries where registering within 90 days of purchase extends it to 5 years at no cost. It covers the glass tank and the cabinet, applies to the first owner only, and requires proof of purchase. Devices supplied with the system, including the ReefATO+, fall under their own warranty.

Why buy from ReefSolution

• Official Red Sea retailer: warranty claims handled with direct factory support
• Store in Laval, Quebec: REEFER systems set up and running, to see before you buy
• Shipping across Canada. Free shipping available depending on order value.
• Real after-sales help, in both languages, from people who run reef tanks themselves
• An RO/DI unit to make your own water at home, and a net cover if jumpers are on your stock list for an open-top tank

Frequently asked questions

How many gallons is the Red Sea REEFER 250 G3?

245 L for the complete system, or 65 US gallons according to Red Sea's own configurator. The display tank alone holds 203 L (53.6 US gal) and the sump 42 L (11.1 US gal).

What are the exact dimensions of the REEFER 250 G3?

The tank measures 90 × 50 × 53 cm (35.4 × 19.7 × 20.9 in). With the cabinet, the whole system stands 140 cm (55.1 in) tall, before adding a light unit.

How many lights does a REEFER 250 G3 need?

Red Sea specifies two ReefLED G2 115 units for this model, and that is what goes into its own REEFER MAX 250 G3. A single fixture leaves the ends of a 90 cm front pane underlit.

Is a REEFER 250 G3 a good reef tank for a family?

It is one of the most popular sizes for exactly that. The volume supports a varied population without turning into an expert-only project, and routine upkeep is easy to share. Read our advice above — it is the question we field most often in store.

How much does a REEFER 250 G3 weigh when full?

Red Sea rates the complete running system at 380 kg (838 lb) over a 90 cm footprint. The empty tank on its own is 55 kg (121 lb).

Should I buy the 200 or the 250?

It is a question of shape as much as volume. The 200 G3 is deeper and narrower; the 250 is longer and shallower. The 250 adds 45 L and a 90 cm front pane, which changes both the aquascape and how the fish use the space.