Red Sea ReefControl - ReefSense Port ExpanderRed Sea ReefControl ReefSense 4Port Expander is the upgrade that turns ReefControl Pro into a full multisensor reef monitoring platform. If youre adding salinity, ORP, ATO, leak detection and temperature on top of pH, the expander gives you the extra ReefSense ports to scale cleanly. The expander plugs into the ReefControl ecosystem and allows you to run up to 7 ReefSense digital probes and sensors on a single controller setupideal for larger reef