N-Fill Smart ATO System - Nature Dimensions

The N-Fill Automatic Top Off System is designed for aquarists who want dependable water level stability with built-in redundancy and intelligent safety features. Engineered for both freshwater and saltwater aquariums, N-Fill delivers consistent top-offs while actively protecting against common ATO failures like stuck floats, siphoning, or overfilling.

Dual Float Sensor Redundancy

Two independent float switches monitor the same water line at all times. If either sensor detects a low water level, the controller immediately initiates a refill. Should one sensor fail, the second continues to function normally—ensuring uninterrupted operation and significantly reducing the risk of missed top-offs compared to single-sensor ATO systems.

Smart Over-Fill Protection

To guard against overfilling, the controller continuously monitors pump runtime. If the pump runs longer than approximately 90 seconds, the system automatically stops filling and triggers an audible alarm along with a solid red Status LED. This controller-based safeguard protects against stuck floats, restricted tubing, or unexpected reservoir behavior.

Intuitive Controller with Clear Status Indicators

The compact controller features three simple buttons for complete control:

• Manual – Press and hold to run the pump for priming or quick refills; release to stop.

• Pause – Temporarily pauses automatic filling for 30 minutes, ideal during feeding or light maintenance.

• Stop – Disables automatic top-offs for 24 hours during major maintenance or water changes.

Three LED indicators provide instant system feedback:

• Power – Confirms the controller is powered and ready

• Filling – Illuminates while water is being added

• Status – Off during normal operation, blinking when paused, and solid red during Stop mode or over-fill alarm

Built-In Siphon Protection

An included siphon breaker connector and protective cover help prevent gravity siphoning when the reservoir is positioned higher than the aquarium. When paired with the included N-Neon ATO Tubing Organizer—which keeps the tubing outlet above the water surface—this adds another critical layer of safety.

Quiet, Compact DC Pump

The included submersible DC pump is small enough to fit in most common ATO reservoirs while still delivering reliable flow and head pressure for nano and mid-size aquariums. Its quiet operation makes it ideal for living spaces and display tanks.

Freshwater & Saltwater Ready

Designed for long-term reliability in both freshwater and marine environments, the N-Fill ATO is suitable for planted tanks, reef aquariums, and fish-only systems alike.

Electrical Safety You Can Trust

The system includes a UL-listed 12 V 1 A power adapter, providing safe, stable power delivery for use around water.

What’s Included

• N-Fill Controller

• Dual float sensors with adjustable mounting holder

• N-Neon ATO Tubing Organizer

• Submersible DC pump

• Water tubing (2 m / 6.5 ft)

• Siphon breaker connector with cover

• UL-listed 12 V 1 A power adapter