Neptune Systems Conductivity Probe

Maintaining consistent salinity in your aquarium is key to the well being of every organism inside it. And, as busy as we sometimes are, we don’t even realize our parameters are out of whack until it’s too late.

The salinity probe will monitor your salinity in parts per thousand (ppt) and provide valuable feedback about your rate of evaporation and changes in the salt concentration in your water.

Compatible with:
Any available Salinity port on the following products: PM2, A2 or A3 Apex Series

The Neptune Systems Conductivity Probe (also often referred to as a Salinity Probe) is a critical sensor for saltwater aquarium hobbyists using an Apex controller. Its primary function is to provide continuous, real-time monitoring of the water's electrical conductivity, which is directly related to its salinity (salt content). Maintaining stable salinity is paramount for the health and well-being of marine fish, corals, and invertebrates.

Key Features and Functions:

Continuous Salinity Monitoring:

The probe constantly measures the electrical conductivity of your aquarium water.
This data is then translated by the Apex into common salinity units such as parts per thousand (ppt), specific gravity (SG), or microsiemens per centimetre (µS/cm). You can choose your preferred display unit in Apex Fusion.
This real-time monitoring is a significant upgrade from periodic manual testing with refractometers or hydrometers.
Lab-Grade Accuracy:

Neptune Systems offers a "Lab Grade" conductivity probe, indicating its precision and reliability for aquarium use.
It's important to note that while it measures conductivity, the Apex then applies temperature compensation to provide an accurate salinity reading, as conductivity is highly temperature-dependent.
Integration with Apex System via PM2 Module:

The Neptune Systems Conductivity Probe does not plug directly into the main Apex head unit (unless you have a very new Apex A3 Pro or similar that might have a dedicated port).
It typically connects to a PM2 Salinity Module. The PM2 module (Probe Module 2) provides the necessary port for the conductivity probe, as well as a temperature probe port (for temperature compensation) and an I/O port.
For Apex A3 models, a conductivity probe port might be integrated directly into the main unit or Energy Bar 832, simplifying the setup.
Real-time Data, Logging, and Graphing:

The live salinity reading is displayed on your Apex Fusion dashboard.
The data is continuously logged, creating graphs that show salinity trends over hours, days, weeks, or months. This allows you to easily spot deviations, sudden drops or spikes, and understand the stability of your system.
Automated Alerts:

This is one of the most powerful features. You can set up custom alerts (email, SMS, push notifications) to notify you immediately if your salinity falls below or rises above your desired range.
Example: "Salinity is below 33 ppt!" or "Salinity is above 37 ppt!"
Automated Responses:

Beyond alerts, the Apex allows for sophisticated automated actions based on salinity readings:

ATO Management: If salinity drops (indicating too much freshwater is being added, e.g., ATO malfunction), the Apex can temporarily disable your auto top-off (ATO) pump.
Dosing Adjustment: While less common for direct control, some advanced users might use salinity data to inform dosing decisions for alkalinity or calcium, though more precise methods like the Trident are generally used for those.
Emergency Shut-off: In extreme cases, if salinity goes dangerously out of range, the Apex could shut off all pumps to protect livestock, though this is usually a last resort after other alarms.

Calibration and Maintenance:

Calibration is Essential: Conductivity probes require regular calibration to maintain accuracy. Neptune Systems recommends using a 53,000 µS (microsiemens) calibration solution, which corresponds to a salinity of approximately 35 ppt (parts per thousand) or 1.026 specific gravity, making it ideal for reef tanks.
Temperature Compensation (TC Factor): Proper temperature compensation is crucial for accurate salinity readings. Ensure a temperature probe is connected to the same module as your conductivity probe, and that the "TC Factor" in Apex Fusion is correctly set (often around 2.2%). The probe and calibration solution should be at the same temperature during calibration for best results.
Cleaning: The probe should be periodically cleaned to remove salt creep, algae, or other buildup that can foul the sensor and lead to inaccurate readings. Gentle wiping or soaking in distilled water or a mild acid solution (like vinegar or citric acid) can help. Avoid scratching the sensing element.

Bubble Management: Microbubbles around the probe can interfere with readings. Place the probe in an area of good flow that is relatively free of constant microbubbles. Some users employ "probe stability kits" or mount the probe upside down to prevent air pockets.
Lifespan: Conductivity probes, like all probes, have a finite lifespan and will eventually need to be replaced, typically every 1-3 years depending on care and water conditions.
Why use a Neptune Systems Conductivity Probe?

For serious reef aquarists, a conductivity probe provides invaluable real-time data and automated protection. It offers peace of mind, allowing you to react quickly to changes in salinity that could otherwise go unnoticed until livestock are stressed or damaged. It's a key component for maintaining the highly stable parameters necessary for a thriving reef.