The SpH-1 probe is used to monitor your water pH. Monitoring pH and EC of the water being fed to the plants is critical. Croptiva only uses professional grade / commercial water probes like the SpH-1. The SpH-1 probe connects to the SWAT-1 module. The probe comes with a 16-ft / 5meter long cable. The SWAT-1 module then sends both probes’ data to the Croptiva controllers. The main controller can then trigger high/low alerts (local and SMS) and provide a visual chart for pH, EC & water temperature. The SpH-1 probe is one of 3 parts that are needed to monitor pH, EC & water temperature. The other two parts required are the SWAT-1 module and the other probe the SEC-1 EC/Temp probe.