Neptune Systems 23″ Liquid Level Sensor with Clip Mount
The Neptune Systems 23 inch Liquid Level Sensor (LLS-23) is an advanced solution for accurately monitoring water levels in larger aquariums, sumps, and reservoirs. It allows continuous measurement of liquid depth in inches or centimeters directly within the Apex Fusion App.
The LLS-23 connects to any available FMM port within the Apex System. Liquid enters the protective plastic envelope surrounding the sensor strip, where patented resistive sensing technology delivers precise and reliable level measurements.
This sensor is particularly suitable for larger systems where greater measuring range is required. A common application is monitoring water levels in roller mat systems, return pump sections, and large reservoirs.
The included clip mount enables easy installation on the side of a sump, aquarium, or container. For euro-braced sumps, the sensor can also be mounted securely to an internal baffle.
The sensor responds to water level changes at an average rate of approximately fifteen seconds per inch. Once calibrated, it provides an accuracy of approximately 0.2 inches. Due to its response characteristics, the LLS-23 is intended for monitoring and analysis rather than immediate control applications such as automatic top-off systems.
Main features:
- 23 inch liquid level measurement range
- Displays water depth in inches or centimeters
- Compatible with Apex Systems via FMM module
- Patented resistive sensing technology
- Includes clip mount for easy installation
- Ideal for large aquariums, sumps, reservoirs, and roller mats
Important installation note:
The sensor ruler section is designed to be in contact with water. The sensor head is epoxy sealed but must not be submerged. Ensure the water level never exceeds the top graduation mark.

