Having the ability to monitor the salinity of your reef tank is a very valuable piece of information.  Usually, if something is to go wrong with your tank, you will usually see a change in salinity from temp, to a top off unit being stuck on, if you have a Neptune Apex Controller we highly recommend investing in the PM2 module and salinity probe.

Features of the Neptune Systems Salinity Expansion Module:

• Monitor/Control Conductivity/Salinity and temperature
• 4 Measurement ranges (0-900 uS/cm, 0-9.0 mS/cm, 0-90.0 mS/cm, 0-50 ppt)
• 6 digital inputs for float switches, water on floor sensors, pressure sensors, etc
• Full data logging support in Apex Base module
• Up to 240 AquaBus modules can be added to the Apex system
• Plug and Play – Automatically recognized when installed into the system
• 2 AquaBus connectors for flexible expansion via AquaBus
• Comes with 3′ AquaBus cable
• Galvanic Isolation for accurate and reliable probe readings
• Led Status Indicator
• Upgradeable firmware
• Compatible with all Apex systems