Index: firmware/App/Controllers/ConductivitySensors.h
===================================================================
diff -u -r54f45c387430e440ab4607451fc84dea61f273f1 -r62ee40b55ed96eb0de1c0f05455eb986f76c1842
--- firmware/App/Controllers/ConductivitySensors.h	(.../ConductivitySensors.h)	(revision 54f45c387430e440ab4607451fc84dea61f273f1)
+++ firmware/App/Controllers/ConductivitySensors.h	(.../ConductivitySensors.h)	(revision 62ee40b55ed96eb0de1c0f05455eb986f76c1842)
@@ -23,6 +23,8 @@
 /**
  *  @defgroup ConductivitySensors ConductivitySensors
  *  @brief Conductivity Sensors monitor module. Monitors and filters conductivity sensor readings.
+ *  The module uses Atlas Scientific EC OEM for conductivity sensors CPi and CPo with probe type K 1.0 and 0.1 respectively.
+ *  The module uses Emstat Pico from PalmSens to measure electrical resistance and convert to conductivity.
  *
  *  @addtogroup ConductivitySensors
  *  @{
@@ -35,17 +37,32 @@
 {
     CONDUCTIVITYSENSORS_CPI_SENSOR = 0,  ///< Inlet water conductivity sensor
     CONDUCTIVITYSENSORS_CPO_SENSOR,      ///< Outlet water conductivity sensor
+    CONDUCTIVITYSENSORS_CD1_SENSOR,      ///< Post-acid concentrate conductivity sensor
+    CONDUCTIVITYSENSORS_CD2_SENSOR,      ///< Post-bicarbonate concentrate conductivity sensor
     NUM_OF_CONDUCTIVITY_SENSORS          ///< Number of conductivity sensors
 } CONDUCTIVITY_SENSORS_T;
 
+/// Conductivity data struct.
+typedef struct
+{
+    F32 roRejectionRatio;                   ///< RO rejection ratio
+    F32 cpi;                                ///< CPi conductivity sensor value
+    F32 cpo;                                ///< CPo conductivity sensor value
+    F32 cd1;                                ///< CD1 conductivity sensor value
+    F32 cd2;                                ///< CD2 conductivity sensor value
+} CONDUCTIVITY_DATA_T;
+
 // ********** public function prototypes **********
 
 void initConductivitySensors( void );
 void execConductivitySensors( void );
 
 void checkInletWaterConductivity( void );
 void checkRORejectionRatio( void );
+void checkConcentrateConductivity( void );
 
+F32 getConductivityValue( U32 sensorId );
+
 BOOL testSetConductivityOverride( U32 sensorId, F32 value );
 BOOL testResetConductivityOverride( U32 sensorId );