Neptune Systems Optical Sensor (OS-1) with Magnet Mount

The Neptune Systems Optical Sensor (OS-1) with Magnet Mount is a fundamental and widely used component in the Apex ecosystem, primarily for precise and reliable water level detection in aquariums. The "magnet mount" version, often referred to as the OS-1M or OS-1 V2 with Mount, makes installation incredibly simple and flexible.

Key Features and Functions:

Optical Sensing Technology:

The OS-1 uses an infrared (IR) optical sensor to detect the presence or absence of water. It emits an IR light beam, and when water is present, the light is refracted differently, signaling a "wet" state. When water is absent, the light is reflected back to the sensor, signaling a "dry" state.
This technology is generally considered more reliable and less prone to sticking or mechanical failure compared to traditional float switches, making it a preferred choice for critical applications like ATO.

Binary State Detection:

Unlike the Liquid Level Sensor (LLS) which provides continuous depth, the OS-1 is a "binary" sensor – it's either OPEN (dry) or CLOSED (wet). This simple, reliable switching makes it ideal for direct control of pumps or other devices based on a specific water level.

Magnetic Mount:

This is the "with Magnet Mount" part. The OS-1 sensor is integrated into a housing that includes a magnetic coupling. A powerful, reef-safe magnet holds the sensor securely in place on the inside of the glass or acrylic, while a matching magnet on the outside of the tank wall provides the necessary clamping force.
Benefits of Magnetic Mount:
Easy Installation: No drilling or messy adhesives required. Simply place the internal magnet and match it with the external magnet.
Flexible Placement: Can be easily repositioned up or down to adjust the trigger point for your water level.
Clean Aesthetic: No visible wires or bulky mounting hardware inside the tank.
Compatibility: Typically designed to mount on glass/acrylic up to 1/4" (approx. 6mm) thick, which covers most sumps and common aquariums.

Connection to FMM Module:

The OS-1 must be connected to one of the four universal sensor ports on a Neptune Systems FMM (Fluid Monitoring Module). The FMM translates the sensor's optical signal into data that your Apex controller can understand.
It cannot be plugged directly into the main Apex module or an I/O Breakout Box.
Integration with Apex Fusion:

Once connected and recognized by your Apex, the status of the OS-1 (wet/dry) is displayed in real-time on your Apex Fusion dashboard.
The Apex logs changes in the sensor's state, allowing you to review historical water level events.

Crucial for Automation and Safety:

The OS-1 is a cornerstone for many critical automation routines:

Automatic Top-Off (ATO): This is its primary application. An OS-1 placed at your desired sump water level can trigger an ATO pump (like the PMUPV2) to turn on when the water level drops (sensor goes DRY) and turn off when the level is restored (sensor goes WET).
High Water Level Alarm: Place an OS-1 higher in your sump or display tank as a failsafe. If the water level rises unexpectedly (e.g., return pump failure causing sump overflow, or ATO malfunction), the sensor will go WET and trigger an alarm and/or shut off pumps to prevent flooding.

Low Water Level Alarm (ATO Reservoir): Place an OS-1 near the bottom of your RODI water reservoir. When it goes DRY, it can alert you that your top-off water is low and needs refilling.
Skimmer Cup Full Alarm: Positioned in your skimmer waste collector, it can alert you or shut off the skimmer when the cup is full to prevent overflows.
Control of Specific Functions: Can be used to activate or deactivate heaters, chillers, or other equipment based on water level changes.

Installation and Setup:

Placement: Determine the desired water level for your ATO or the critical high/low level for an alarm.

Mounting: Clean the inside and outside of the glass/acrylic where you intend to mount the sensor. Place the OS-1's internal magnetic half on the inside of the tank/sump wall. Align the external magnet on the outside of the wall to securely clamp the sensor in place.
Ensure the optical eye of the sensor is positioned exactly at the water level you wish to monitor.

Connection: Plug the cable from the OS-1 into any available sensor port on your FMM module.

Configuration in Apex Fusion:
Access your Apex Fusion dashboard. The Apex should auto-detect the OS-1.
Navigate to the FMM's configuration page and the specific port. Name the sensor descriptively (e.g., "Sump ATO Level," "Sump High Level," "RODI Low Level").
Use the Apex Fusion "Tasks" wizard (e.g., "Auto Top-Off Kit" or "Add a Level Sensor") to easily set up your ATO logic, alarms, and associated pump control. You'll typically program based on the sensor's state changing from OPEN to CLOSED or vice-versa.

The Neptune Systems Optical Sensor (OS-1) with Magnet Mount is a highly reliable and user-friendly sensor that forms the backbone of many essential monitoring and automation tasks in an Apex-controlled aquarium, particularly for maintaining stable water levels and preventing overflows or dry-runs.