AutoAqua Smart ATO Nano G2

The AutoAqua Smart ATO Nano G2 is a plug-and-play auto top-off system built for nano reefs, AIO tanks, and small saltwater setups. The G2 generation uses a contactless optical sensor instead of a float, so there is nothing to stick, jam, or clog with salt creep. Browse our full lineup of saltwater equipment and pair it with the right reservoir below.

Why Reefers Trust Smart ATO Nano

• Optical, not float-based. An infrared sensor reads water level through the glass of the sensor body. No moving parts means no stuck floats and no salt-creep failures.
• Built-in safety logic. A 60-second continuous-run lockout shuts the pump off and sounds an alarm if it thinks the sensor is failing. Protects your livestock from a flood or a salinity crash.
• Low-water alarm. Audible beep when the RO/DI reservoir runs dry.
• Plug and play. Pump, sensor, controller, and wiring all in the box. No soldering, no DIY.
• Magnetic mount. Sensor attaches with a slim neodymium magnet, no clamps to drill or zip-tie.

How It Works

1. Mount the optical sensor on the sump or display wall at the desired water line.
2. Drop the pump in your RO/DI reservoir.
3. Run the dosing line back to the tank or sump.
4. Plug in. The sensor watches the water line and triggers the pump when evaporation drops it below the set point.

Specifications

Recommended Pairings

• IceCap ATO Reservoir 5 Gallon — compact reservoir for nano setups
• IceCap ATO Reservoir 10 Gallon — longer runtime between refills
• IceCap 4-Stage RO/DI 75 GPD — make your own top-off water
• AutoAqua Titanium S2 Inline TDS Meter — keep an eye on your RO/DI output

FAQ

Will it work in a freshwater tank?
Yes. The optical sensor reads water level the same way regardless of salinity, so freshwater planted and shrimp tanks work just as well as reefs.

How big a reservoir should I run?
For most nano reefs (10 to 40 gallons), a 5-gallon reservoir lasts 1 to 2 weeks. Larger tanks or warmer rooms go through more water, so a 10-gallon reservoir is a better fit.

What happens if the pump runs too long?
The controller cuts power after 60 seconds of continuous run and triggers an audible alarm, so a stuck-on pump cannot flood your tank.

Can I use it with a Kalkwasser reactor or two-part dosing?
The pump can feed a Kalk reactor inline, just keep the runtime modest. For true Kalk drip control, a dedicated Kalk doser plus this ATO works well together.