Neptune Liquid Level Sensor 4"

Accurate Water Depth Monitoring for Small Aquarium Reservoirs

The Neptune Liquid Level Sensor (LLS-4) introduces precise water depth measurement to your sump, ATO reservoirs, or additive containers — with live monitoring via your Apex Fusion app. This 4” sensor gives hobbyists the ability to track water levels in inches or centimeters, providing peace of mind and better aquarium management.

Key Features & Benefits

• Real-time water depth measurement (inches or centimeters)

• Ideal for small sumps, ATO reservoirs, and dosing containers

• Easily monitor water levels via the Apex Fusion app

• Patented resistive sensing technology for reliable, accurate readings

• Fastens securely with included mounting clip for sump, tank or container

• Compatible with A2 Apex with FMM and A3 Apex controllers

• 3-meter cable length for flexible positioning

How It Works

Liquid enters the plastic sheath surrounding the thin LLS sensor material. The patented resistive sensing technology reads the depth of water in your container and communicates the data to your Apex system for precise, on-demand monitoring.

Installation & Compatibility

Easily mount the LLS sensor to your sump wall, baffle, or container with the included clip. The 4" sensor is ideal for compact applications like ATO reservoirs, additive containers, or nano sumps.

Compatibility:
✔️ A2 Apex (with FMM module)
✔️ A3 Apex controllers (via FMM ports)

Not compatible with A1 (Apex Classic) controllers.

Best Uses

• Monitor additive container levels to verify dosing schedules

• Keep an eye on small ATO reservoirs and refill proactively

• Track liquid levels during aquarium maintenance

• Ensure precise top-off rates for evaporation control

Sensor Responsiveness & Accuracy

• Responds to water depth changes at ~15 seconds per inch

• Accurate to ~0.2 inches once calibrated
  Not recommended for immediate-response ATO control