Living Ecosystem Aquarium - Auto Top-Off (ATO) Troubleshooting & Maintenance Guide

The Auto Top-Off (ATO) system in your Living Ecosystem Aquarium is designed to automatically maintain stable water levels in the rear filtration chamber, on the far right-hand side of the aquarium. It includes a dual sensor with a visual LED indicator, and a small pump located in the freshwater reservoir inside the cabinet. Together, they keep salinity levels stable and support healthy biological cycling.

ATO Failure – Causes and Consequences:

If the ATO stops working, water lost through evaporation is not replaced. This causes salinity to rise, putting fish and corals at risk and destabilising the ecosystem.

A flashing red LED on the ATO sensor means the system is not topping up water. This can be caused by a low or empty reservoir, a blocked pump, or incorrect sensor alignment. Prompt troubleshooting is required to restore water balance.

Quick Diagnostic Tip: Bubbles in the Aquarium
One of the most visible signs that your ATO has run dry is persistent bubbles in the aquarium. This happens when the pump stops drawing water and pushes air instead. Action: Check the reservoir—if it's low or empty, top it up with 10–12 L of freshwater.

Interpreting the ATO LED Light:

  • LED displays green when the system is stable.
  • LED flashes green during top-up cycles.
  • LED flashes red when the system is not topping up — follow troubleshooting steps below.

Understanding the ATO sensor:

  • ATO sensor sets the water height in the rear filtration chamber.
  • Proper alignment ensures silent operation and adequate gas exchange.
  • A small external magnet is factory-positioned on the back glass of the aquarium to mark the correct sensor position — this should not be moved. The sensor attaches inside, aligned to this marker.
  • If the sensor is not correctly positioned, water level readings may be inaccurate and cause the system to fail to top up or to cycle unnecessarily.

Troubleshooting Steps

1. Check water level in the reservoir

  • Minimum 2L is required for the pump to operate
  • Refill to 10–12L (recommended)
  • If water is low, the LED may turn red and the pump may push bubbles

2. Reset the ATO sensor

  • Turn off the power at the mains (not just the cabinet power board)
  • Wait 5 seconds, then turn the power back on
  • The sensor should turn green and resume operation

3. Check pump function

  • Remove the pump from the reservoir
  • Inspect the impeller for blockages or debris
  • Ensure the power connection is secure

 

4. Check sensor alignment

  • The sensor must be attached inside the aquarium, aligned with the external magnet marker
  • Misalignment can cause false water level readings or prevent the sensor from activating

Maintenance and Top-Up Instructions

  • Check the reservoir weekly
  • Top-up volume: 5–12L
  • Do not exceed 12L to avoid excessive lifting weight
  • Water can be added using a clean, dedicated jug or container
  • Alternatively, remove the reservoir and fill at the tap — disconnect the hose from the pump, refill, then reconnect
  • Filtered tap water is preferred; good quality tap water is usually sufficient
  • The aquarium typically evaporates ~2L per week depending on climate

Need More Help?

Still not working after following all troubleshooting steps?

Contact Living Oceans Support at support@livingoceans.com.au for further assistance.

To help us resolve your issue quickly, please include the following information in your email:

  • Your aquarium model (e.g. Cube 80L or Cube 130L)
  • A brief description of the issue
  • Steps you’ve already taken to troubleshoot
  • Photos or video if relevant (e.g. sensor placement, pump setup, LED colour)

Our support team will assist with diagnostics and, if necessary, arrange a replacement part or technician visit.

We’re here to ensure your Living Ecosystem stays healthy and thriving.