Neptune Systems Optical Sensor (OS-1)
This sensor plugs into your FMM and, using reflected infrared light, will signal your Apex when it changes state from being wet to dry or dry to wet. This sensor can be used for constructing your own ATO (auto-top-off), as a high-level warning sensor in your sump, water storage level sensor, and much more. The sensors can be mounted into custom brackets or through a hole in a vessel. Included are a fastening nut and silicone washer. The sensor has a wire length of 3 meters. These sensors are sold individually.
The Neptune Systems Optical Sensor (OS-1) is a fundamental and widely used water level sensor within the Neptune Systems Apex aquarium controller ecosystem. It's designed for simple yet highly reliable detection of the presence or absence of water at a specific point.
It's important to clarify that while the OS-1 refers to the core optical sensor technology, it's typically sold and used in a specific form factor or with a mounting solution. The most common modern version incorporates a magnet mount (often called OS-1M or OS-1 V2 with Mount, or simply the MOS, Magnetic Optical Sensor). However, the underlying "OS-1" functionality describes its core operation.
Key Features and Functions of the OS-1 (Optical Sensor):
Optical Sensing Technology:
The OS-1 uses an infrared (IR) LED and receiver to detect water. The sensor emits a beam of infrared light.
When dry: The light is reflected back internally to the receiver, indicating no water.
When wet: The light is refracted (bent) away by the water, so it does not return to the receiver, indicating the presence of water.
This method is highly reliable and has significant advantages over traditional mechanical float switches, which can become stuck due to salt creep, snails, or wear.
Binary State Detection:
The OS-1 is a "binary" sensor, meaning it has two states:
OPEN (or DRY): No water is detected.
CLOSED (or WET): Water is detected.
This simple ON/OFF switching makes it perfect for triggering automated actions when a water level crosses a specific threshold.
Accuracy and Repeatability:
Optical sensors are known for their high accuracy and repeatability, ensuring consistent and precise detection of the water level.
Versatile Mounting (often with magnetic mount):
While the "OS-1" refers to the sensor itself, it's most commonly integrated into a housing with a magnetic mount. This allows for easy and flexible placement on glass or acrylic sumps, aquariums, or reservoirs (typically up to 1/4" or 6mm thick for older versions, up to 1/2" or 12.7mm for the newer MOS versions).
Some older or less common versions might have suction cups or other mounting options, but magnetic mounting is the standard for ease of use.
Connection to FMM Module:
The OS-1 (regardless of its specific mounting) must be connected to one of the four universal sensor ports on a Neptune Systems FMM (Fluid Monitoring Module). The FMM acts as the crucial interface, interpreting the optical signal and relaying the wet/dry status to your main Apex controller.
It cannot be plugged directly into the Apex head unit or an I/O Breakout Box.
Seamless Apex Fusion Integration:
Once connected to the FMM and detected by your Apex, the real-time status of the OS-1 is displayed prominently on your Apex Fusion dashboard.
All changes in the sensor's state are logged and graphed in Apex Fusion, providing a historical record that can be invaluable for troubleshooting or understanding water level trends.
Essential for Automation and Safety:
The OS-1 is a cornerstone for many critical automation and safety routines in an Apex-controlled aquarium:
Automatic Top-Off (ATO): Its primary application. An OS-1 placed at the desired normal water level in your sump will go DRY when evaporation occurs, triggering an ATO pump (like the PMUPV2) to add RODI water until the sensor goes WET again, turning the pump off.
High Water Level Alarm/Failsafe: An OS-1 placed higher in the sump or display tank can act as an overflow failsafe. If the water level rises unexpectedly (e.g., ATO malfunction, return pump failure causing sump overflow), the sensor going WET can trigger an audible alarm, send notifications, and/or shut off pumps to prevent flooding.
Low Water Level in Reservoir: An OS-1 placed near the bottom of your RODI top-off reservoir will go DRY when the water level is critically low, sending an alert to your phone to refill.
Skimmer Cup Full Alarm: Positioned in a skimmer waste collection cup, it can detect when the cup is full and shut off the skimmer to prevent messy overflows.
Other Custom Controls: Any application where you need a simple ON/OFF switch based on water presence.
Installation and Setup:
Placement: Identify the specific water level you want to monitor or control (e.g., normal sump level for ATO, a high-level overflow point, or a low-level alert in a reservoir).
Mounting: If using the magnetic mount version, clean the tank/sump wall. Position the internal magnetic half of the sensor at the desired level, and secure it with the external magnet. Ensure the optical "eye" is at the exact point where you want to detect the water level.
Connection: Plug the OS-1's cable into any available sensor port on your Neptune Systems FMM module.
Configuration in Apex Fusion:
Access your Apex Fusion dashboard. Your Apex controller will typically auto-detect the new sensor.
Navigate to the FMM's configuration page and the specific port. Give the sensor a descriptive name (e.g., "Sump_ATO," "Sump_Overfill," "RODI_Empty").
Use the Apex Fusion "Tasks" wizard (e.g., "Auto Top-Off Kit" or "Add a Level Sensor") to easily set up the desired automation, alarms, and pump control based on the sensor's OPEN/CLOSED state.
In essence, the Neptune Systems OS-1 (in its various mounted forms, including the MOS) is an indispensable, highly reliable, and user-friendly optical water level sensor that provides critical monitoring and robust automation capabilities, greatly enhancing the safety and stability of any Apex-controlled aquarium.
