Waterbox AIO Tank Modification Guide: Reef Cube Series

The Waterbox Cube series is built better than any nano AIO in its price class — but the stock return pump and media setup still leave room on the table. This waterbox aio tank modification guide draws on two decades of reef builds at Gensou Aquascaping in Everton Park. Across the Cube 10, 16, and 20 the modifications follow the same logic: upgrade the return, improve media flow, and plumb in proper ATO and skimmer fittings. The result is a tank that performs like a custom build at plug-and-play cost.

Quick Facts

• Models covered: Cube 10 (38L), Cube 16 (61L), Cube 20 (76L)
• Stock return pump: Sicce Syncra Silent 1.0 on Cube 10, 1.5 on Cube 20
• Rear chambers: four — skimmer, refugium/media, heater, return
• Stock skimmer: none — chamber is pre-sized for nano skimmers
• Recommended skimmer: Tunze 9001 or NYOS Quantum 120
• Singapore price: Cube 10 $450, Cube 16 $650, Cube 20 $780 approximate
• Typical full-mod build cost: $1,200-1,800 including livestock

Return Pump Upgrade

The stock Syncra Silent is reliable but fixed-speed. Swap to a Sicce Syncra SDC 2.0 or 3.0 DC-controllable pump for variable flow. The SDC controller allows ramping and night mode, reducing flow during lights-off to let detritus settle where the skimmer intake catches it. On the Cube 20, an Ecotech Vectra S1 fits the return chamber if you prefer app-controlled programming.

Skimmer Chamber Setup

Chamber 1 is pre-sized for nano skimmers. The Tunze 9001 (for Cube 10) and NYOS Quantum 120 (for Cube 16 and 20) fit without modification. Water level in the skimmer chamber is critical — measure with a ruler after running the new return pump for 24 hours and adjust pump output to hit the skimmer’s recommended level (typically 130-150mm). Too deep drowns the skimmer, too shallow starves it.

Refugium Conversion

Chamber 2 ships as a media chamber but converts easily to a refugium. Add a Kessil H80 Tuna Flora or Amazonas NV24 on a reverse photoperiod, a handful of chaeto, and some live rock rubble. The refugium exports nitrate and phosphate naturally while providing pod habitat for dragonets and gobies. Drop-in conversion takes ten minutes and the benefit shows within six weeks.

Return Plumbing Upgrade

The stock return nozzle on all three Cubes is a fixed 3/4-inch elbow. Replace with a RFG nozzle (Random Flow Generator) or swap for a locline gooseneck for adjustable aim. The RFG spreads flow into a wide diffused pattern that eliminates dead spots on the rockwork, which is particularly useful on the deeper Cube 20 where the stock nozzle leaves the lower rear unlit by flow.

ATO Integration

Chamber 4 is the return chamber and the designated ATO spot. An Autoaqua Smart ATO Micro with the optical sensor mounted on the chamber side glass handles top-off automatically. Run a 3/16-inch tubing line from a 10-litre reservoir tucked in the cabinet. Evaporation in a Singapore aircon room runs 400-900ml per day depending on Cube size and skimmer airflow.

Wavemaker Additions

All three Cubes benefit from an added powerhead. Cube 10 pairs well with a single Sicce Voyager Nano 2000 or AI Nero 3; Cube 16 and 20 accept a pair of Nero 3s opposed for gyre flow. Target 25-40x tank-volume flow including the return. Magnet-mount models are cleaner than suction-cup units and hold firmly on the 10mm Waterbox glass.

Common Modifications Worth Skipping

Drilling the overflow for a larger external sump adds complexity without meaningful gain on a nano this size. Swapping the skimmer chamber glass dividers rarely pays back the effort. The Waterbox chambers are already well-proportioned for most nano reef workflows — focus mods on pump, skimmer, and ATO rather than glasswork.

Related Reading

Nano Reef AIO Tank Modifications
All In One Reef Tank Comparison
Best Protein Skimmers Nano Reef
Nano Reef ATO Setup Guide
Return Pump Selection Reef Tank