Eshopps Aqua-Fuge Cube Nano Review: A Compact Sump for Small Reef Tanks

Introduction

Small sumps are one of the harder pieces of reef equipment to shop for, largely because most nano tanks arrive as all-in-one systems rather than as drilled tanks with their own overflow and sump. The Eshopps Aqua-Fuge Cube Nano is aimed squarely at the keeper who went the other route and wants a compact sump that still covers the essentials. It combines a quiet water entry, mechanical filtration, a refugium, room for a skimmer, and a return chamber in a small, deliberately simple package, so you do not have to build a DIY sump out of a 10 or 20 gallon tank. The unit is finished in white and blue, and the box includes the sump itself, a corrugated drain hose, a filter sock, and instructions.

Who the Aqua-Fuge Cube Nano Is For

The Cube Nano measures 14 x 14 x 16 inches and is rated for aquariums between 10 and 35 gallons. That makes it a natural match for small display tanks, and it sits comfortably inside stands built around compact footprints. It can also be squeezed into some stands intended for smaller standard aquariums.

Inside, the sump divides into three working zones: a 7.5 x 8.5 inch skimmer section, roughly 5 x 8.5 inches of refugium space, and a 3.5 x 5.5 inch return section. Those proportions are the whole point of the product. They give a nano system real filtration capacity without demanding a large cabinet underneath it.

If your tank is a small drilled aquarium with its own modest overflow, this is the setup the sump was designed around. If you run an all-in-one system with chambers built into the back, this product is not aimed at you.

Design and Flow Path

A single bulkhead handles the drain line on the Nano version. That suits simpler overflow systems where one drain runs down to the sump and one return line goes back up to the overflow. For overflow systems that use the Herbie method and call for an auxiliary or backup drain, adding a secondary drain over the skimmer or refugium section takes minimal effort. Eshopps also offers a medium version of this sump, which is larger and carries a pair of bulkheads for drains instead of one, and shares many of the same features.

The flow path is more considered than the small footprint suggests. Water enters through the bulkhead and immediately splits into two routes. One route diverts part of the water into the refugium section. The other passes through the filter sock and into the skimmer section. Water leaving the refugium travels through a large vertical baffle fitted with an equally large coarse foam pad, then runs underneath the skimmer section on its way to the return. Water from the skimmer section reaches the return directly through an adjustable baffle, which lets you set the water height in the skimmer section to suit the skimmer you install.

Managing two separate paths in a sump this small matters. It keeps the skimmer and the refugium from having water pushed through them at full force, which is a common compromise in compact sumps.

Skimmer and Refugium Chambers

At 7.5 x 8.5 inches, the skimmer section is large enough for a number of compact in-sump protein skimmers. Fitting a capable skimmer into a very small sump is normally the hardest part of the whole exercise, so that chamber size is a meaningful advantage. Eshopps also makes a much smaller protein skimmer that mounts magnetically to the side of a sump, the back of an all-in-one, or inside a quarantine tank for keepers who want to free up chamber space later.

The refugium section is generous for its class. It offers enough room for macroalgae and roughly matches the volume of two smaller macroalgae reactors. Lighting it is straightforward with a puck-style refugium LED or a submersible option. If macroalgae is not part of your plan, the same space holds a range of popular biomedia or a smaller media reactor, so it stays useful either way.

For many nano keepers, the combination of a working skimmer chamber and a genuine refugium in one compact body is the reason to choose this sump over a homemade alternative.

Return Chamber and Pump Options

The return section is the tightest part of the layout at 3.5 x 5.5 inches, and it does narrow your pump choices. That said, it has just enough room for a reliable controllable DC pump such as the Octo VarioS-2, which includes an auto shutoff switch so it does not run dry. A pump of that type gives you speed control and dependable operation in a chamber with very little spare space. There is also a cosmetic detail worth noting: the drain tube on the sump is red, and this pump carries a white body with a red base, so the two look intentional together.

Maintenance and Everyday Use

Routine work on the Cube Nano is largely straightforward. A lid sits over the filter sock, which keeps salt spray and splashes contained, and the door opening is big enough to get the sock and a hand in and out without contortions. The large coarse foam pad slides in and out easily and sits vertically when removed, so dealing with debris that collects above the sump is simple.

The one area that asks for a little more effort is the pair of baffles that sandwich the foam pad, along with the channel that travels under the skimmer section. The gap between those baffles is roughly 3/4 inch, so a sponge or brush on a handle helps when a scrub is needed. It is also easy to attach a tube to a pump underneath the skimmer section to clear that channel. Picking up those two cleaning items alongside the sump makes those spots much quicker to service.

None of this is unusual for a sump of this size. It is simply worth planning for rather than discovering later.

Things to Consider Before Buying

A few limitations are worth weighing before you commit.

• The return section is compact, so confirm that your preferred pump fits within 3.5 x 5.5 inches before ordering.
• Cleaning the baffle gap and the channel under the skimmer section is easier with a long-handled brush or sponge and a pump-driven tube.
• The Nano has a single drain bulkhead. Dual-drain Herbie setups require adding a second drain over the skimmer or refugium section.
• If you want more volume and a factory dual-drain arrangement, the larger medium version of the same sump line is the alternative.

Buying Advice

The strongest case for the Aqua-Fuge Cube Nano is a drilled nano tank between 10 and 35 gallons that needs a proper sump rather than a DIY build. The chamber layout gives you a real skimmer section, a refugium that can run macroalgae or media, and a return zone, all within a footprint that fits small stands. The quiet water entry, filter sock, splash lid, and adjustable baffle round out a package that is simple by design rather than short on features.

Match the sump to what you actually plan to run. Check your pump dimensions against the return chamber, decide in advance whether you want macroalgae or media in the refugium, and confirm your overflow type against the single drain bulkhead. Do that, and this is a compact sump that will quietly do its job for years without asking for much attention.

Conclusion

The Eshopps Aqua-Fuge Cube Nano solves a specific problem well: it gives small drilled reef tanks a feature-rich sump without forcing a DIY project or a large cabinet. The dual flow path, adjustable baffle, skimmer chamber, and usable refugium are the highlights, while the tight return section and the single drain bulkhead are the honest trade-offs. For a nano reefer who values simplicity and a clean look under the tank, it is an easy option to consider.