Early Access Special: get $20 off the retail price. You’ll receive one of the first-batch units of N-Fill, and we guarantee your satisfaction. Otherwise, we will issue a full refund. Offer valid until 11/30.

Ships in 3 business days.

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 reef tanks.

Key Features

• Dual float sensors and advanced refill logic
  Two independent float switches monitor the same water line. The controller starts a refill whenever either sensor detects low water, so even if one sensor fails, the other still triggers top offs. This redundancy helps ensure you do not miss refills, providing an extra layer of stability compared to most other ATOs on the market.
  
• Smart over-fill protection
  If the pump runs for more than about 90 seconds, the controller pauses filling and triggers an audible alarm with a red Status LED. This controller based fail safe helps prevent overfilling if a float sticks low, flow is restricted, or the reservoir is not behaving as expected, giving you time to check reservoir level, tubing, and sensors before anything goes wrong.
• Intuitive controller with clear status indication
  Three buttons give you quick, simple control:
  • Manual – hold to run the pump for priming and quick refills, release to stop.
  • Pause – press once to enter a 30 minute pause, ideal when feeding or doing light maintenance. Press again to resume normal operation.
  • Stop – press once to disable automatic filling for 24 hours during larger maintenance or when you want the ATO on standby. Press again to return to normal operation.
  Three LED indicators provide quick, at a glance status:
  • Power – shows whether the controller has power and is ready.
  • Filling – lights up when the pump is running and water is being added to the tank.
  • Status – off during normal operation, blinking when paused, and solid red during Stop mode or when an overfill alarm is active.
• Siphon breaker included
  The included siphon breaker connector and cover help stop gravity siphoning when the reservoir water level is higher than the display tank. Combined with the N-Neon ATO Tubing Organizer keeping the outlet above the water surface, you get an extra layer of safety.
• Quiet, compact DC pump
  The submersible DC pump is small enough to fit common ATO reservoirs while providing enough head and flow for most nano and mid size tanks.
• Freshwater and saltwater ready
  Built for long term use in both freshwater and marine environments, from planted tanks to reef systems.
• UL listed power adapter
  Ships with a 12 V 1 A UL listed power supply for safe, stable operation near water.

What’s Included

• N-Fill controller
• Dual float sensors with graduated 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

Technical Specifications

Warranty

1 year limited warranty