N-Fill ATO User Guide

N-Fill Smart Auto-Top-Off System

N-Fill Smart Auto-Top-Off System keeps your aquarium water level stable so salinity and waterlines stay consistent with minimal effort. Dual float sensors with built-in redundancy, a quiet DC pump, and an intelligent controller with fail-safe protection work together to deliver reliable, hands-free top-offs for both freshwater and saltwater tanks.

About Nature Dimensions

Founded in Silicon Valley, Nature Dimensions is dedicated to bridging the gap between cutting-edge innovation and the beauty of the natural world. Our mission is to empower hobbyists with advanced, elegant solutions that help them integrate nature into everyday life. Our products combine sleek design with robust, industrial-grade durability for a perfect harmony between technology and nature.

Key Features

• Dual float sensors for stable water levels. Two independent float switches monitor the same water line. The controller starts a refill whenever either sensor detects low water, so even if one switch sticks or fails, the other still triggers top-offs.
• Fail-safe overfill protection. If the pump runs continuously for about 90 seconds, the controller pauses filling, sounds an audible alarm, and turns the Status LED red so you can inspect the reservoir, tubing, and sensors before water can overflow.
• Intuitive controller with clear status indication.

  Three buttons keep control simple:

  • Manual — Hold to run the pump for priming or quick refills, then release to stop.
  • Pause — Press once to pause automatic filling for 30 minutes during feeding or light maintenance; press again to resume.
  • Stop — Press once to disable automatic filling for 24 hours during major work or when you want the ATO on standby; press again to exit.

  LED indicators deliver at-a-glance feedback:

  • Power — Lets you know the controller is powered and ready.
  • Filling — Lights up while the pump runs and water is being added.
  • Status — Off during normal operation, blinking while paused, and solid red during Stop mode or an overfill alarm.
• Siphon breaker included. The siphon breaker connector and cover stop gravity siphoning when the reservoir water level is higher than the display tank, especially when paired with the N-Neon ATO Tubing Organizer that keeps the outlet above the water surface.
• Quiet, compact DC pump. A submersible 12 V pump fits most reservoirs yet provides enough head pressure and flow for common nano and mid-sized tanks.
• Freshwater and saltwater ready. Designed for long-term use in planted freshwater systems and saltwater aquariums alike.
• UL-listed power adapter. Ships with a 12 V 1 A UL-listed supply for safe, stable operation near water.

Specifications

In the Box

• N-Fill Controller × 1
• Tubing Organizer × 1
• Float Sensors × 2
• Sensor Holder × 1
• Submersible Pump × 1
• Water Tubing (2 m / 6.5 ft) × 1
• UL-Listed Power Adapter (12 V 1 A) × 1
• Siphon Breaker Connector × 1

Installation Guide

1. Mount the Sensors
   • 1.1Install and secure both float switches into the sensor holder. Mount the sensor holder onto the adjustable arm.
   • 1.2Mount the assembled sensor holder onto the tank rim and adjust the sensors' height to your desired water line.
2. Connect the Tubing
   • 2.1Cut the tubing into two sections: the shorter section (about 2/3 the height of the reservoir) connects the pump to the siphon breaker, and the longer section runs to the tank.
   • 2.2Connect the pump to the siphon breaker with the shorter section, pushing the tubing fully over each barb.
   • ⚠️Slide the cover over the connector to prevent water from spraying out of the reservoir.
   • 2.3Ensure the siphon breaker stays inside the reservoir, above the waterline.
   • ⚠️This breaker stops gravity siphoning when the reservoir sits higher than the tank.
3. Route the Tubing
   • 3.1Run the longer tubing from the siphon breaker connector to the tank without kinks.
   • 3.2Route the line through the tubing organizer and clip the organizer to the tank rim.
   • ⚠️Keep the refill tubing outlet above the tank water surface at all times to avoid siphoning.
4. Connect the Components to the Controller
   • Connect the sensor, pump, and power adapter to the controller.
5. Prime & Test
   • 5.1Power on the controller. The Power LED should light up green.
   • 5.2Hold the Manual button to run the pump until a steady, bubble-free stream exits the refill tubing, then release the button to stop.
   • 5.3Gently press each float sensor downward one at a time. Because either switch alone triggers a refill, the Filling LED should light up every time you depress a sensor and turn off as soon as you release it.

Leak Check

• With the Manual button held, inspect every connector, the siphon breaker, and the tubing organizer for drips.
• Confirm the siphon breaker vent stays above the reservoir waterline so air can enter if a siphon tries to form.
• Dry any moisture, re-seat tubing if needed, and observe the outlet for a full minute to ensure it remains above the tank water surface when the pump stops.

Controller Overview

Buttons and Manual Controls

Overfill Timeout

If refilling continues for more than ~90 seconds, the controller halts the pump and sounds an alarm. The Status LED remains red until you remedy the cause and reset the controller.

LED Indicators

Alarms & Troubleshooting

Alarm Recovery

When the overfilling alarm triggers, the system stops for 24 hours. Identify and fix the cause before resuming.

Troubleshoot the Cause

• Verify the reservoir contains enough water and the pump is fully submerged.
• Ensure both float switches move freely and are not obstructed.
• Confirm tubing is correctly routed and the outlet remains above the tank waterline.
• Look for kinks, air locks, or debris restricting flow.

Recover the Controller

• Manual recovery: Press the Stop button once to clear the red Status LED and resume operation.
• Auto recovery: The controller automatically resets to normal every 24 hours.

Maintenance

• Wipe down the sensor holder, float switches, and tubing organizer with a soft cloth.
• Inspect the siphon breaker cover and vent to ensure they stay above the reservoir waterline and free of salt crystals.
• Confirm all connections remain secure.
• Tap the floats up and down while watching the Status LED to confirm smooth movement and consistent feedback.

Safety Instructions

• Use only the included UL-listed power adapter.
• Plug the adapter into a GFCI-protected outlet to reduce shock risks near water.
• Mount the controller in a dry location, away from splashes or salt creep.
• Do not submerge the controller in water.
• Never run the pump dry; keep it fully submerged in the reservoir.
• Ensure the siphon breaker connector and cover remain above the reservoir waterline to prevent siphoning.
• Keep the refill tubing outlet above the aquarium water surface and secured by the organizer.
• Disconnect power before cleaning or performing maintenance.
• Keep the device out of reach of children and pets.

Warranty & Support

Nature Dimensions provides a 1-year limited warranty covering manufacturing defects for the N-Fill Smart Auto-Top-Off System.

What’s Covered

• N-Fill controller
• Dual float sensors and sensor holder
• Tubing organizer
• Bracket
• Submersible pump
• Siphon breaker connector
• UL-listed 12 V 1 A power adapter

What’s Not Covered

• Any component not listed above as covered
• Water intrusion into the controller or power adapter
• Damage from improper installation, misuse, or modification
• Consumables such as cut tubing or third-party accessories
• Service performed by non-authorized technicians
• Damage caused by power surges, lightning, or incompatible equipment

How to File a Warranty Claim

1. Email support@naturedimensions.com with your proof of purchase and a description of the issue.
2. Attach photos or video if the problem is visible.
3. Our team will reply within 2 business days with next steps or return instructions.

Customer Support

Note: Warranty coverage applies in the original country of purchase unless local laws provide otherwise. Nature Dimensions is not responsible for indirect, incidental, or consequential damages.