Index: firmware/App/Monitors/Conductivity.h
===================================================================
diff -u -rdc3647b737971d298748796d2455b3e021325d8a -rae31b4c999dccae70fb40fb9d98a4380ce2c7415
--- firmware/App/Monitors/Conductivity.h	(.../Conductivity.h)	(revision dc3647b737971d298748796d2455b3e021325d8a)
+++ firmware/App/Monitors/Conductivity.h	(.../Conductivity.h)	(revision ae31b4c999dccae70fb40fb9d98a4380ce2c7415)
@@ -1,24 +1,26 @@
 /**************************************************************************
 *
-* Copyright (c) 2024-2024 Diality Inc. - All Rights Reserved.
+* Copyright (c) 2024-2026 Diality Inc. - All Rights Reserved.
 *
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * @file    Conductivity.h
 *
-* @author  (last)      Vinayakam Mani
-* @date    (last)      10-Sep-2024
+* @author  (last)      Michael Garthwaite
+* @date    (last)      02-Feb-2026
 *
 * @author  (original)  Vinayakam Mani
-* @date    (original)  10-Sep-2024
+* @date    (original)  13-Sep-2024
 *
 ***************************************************************************/
 
 #ifndef __CONDUCTIVITY_H__
 #define __CONDUCTIVITY_H__
 
 #include "DDCommon.h"
+#include "DDDefs.h"
+#include "ConductivityTeensy.h"
 #include "ConductivitySensors.h"
 
 /**
@@ -33,6 +35,9 @@
 
 // ********** public definitions **********
 
+#define RO_REJECTION_RATIO_OUT_OF_RANGE_VALUE        100.0F   ///< Out of range value for RO rejection ratio when CPi conductivity is zero.
+
+#pragma pack(push, 1)
 /// Conductivity data struct.
 typedef struct
 {
@@ -41,14 +46,47 @@
     F32 d29Cond;                                              ///< CD3 conductivity sensor value
     F32 d43Cond;                                              ///< CD4 conductivity sensor value
     F32 d74Cond;                                              ///< CD5 conductivity sensor value
-} CONDUCTIVITY_DATA_T;
+} DD_CONDUCTIVITY_DATA_T;
 
+/// Conductivity data struct.
+typedef struct
+{
+    F32 p9Conductivity;                                       ///< (P9) conductivity sensor value
+    F32 p18Conductivity;                                      ///< (P18) conductivity sensor value
+} FP_CONDUCTIVITY_DATA_T;
+
+/// RO rejection ratio data struct.
+typedef struct
+{
+    F32 rawRORejectionRatio;                                 ///< RO rejection ratio during tank full and fill state
+    F32 rawRORejectionRatioTankFill;                         ///< RO rejection ratio during tank fill state
+    F32 avgRORejectionRatio;                                 ///< RO rejection ratio average during tank full and fill state
+    F32 avgRORejectionRatioTankFill;                         ///< RO rejection ratio average during tank fill state
+    U32 genPermeateState;                                    ///< Permeate tank state
+} RO_REJECTION_RATIO_DATA_T;
+#pragma pack(pop)
+
 // ********** public function prototypes **********
 
 void initConductivity( void );
 void execConductivity( void );
+F32 getFilteredConductivity( CONDUCTIVITY_SENSORS_T sensor );
+F32 getFilteredConductivitySensorTemperature( CONDUCTIVITY_SENSORS_T sensor );
+F32 getRORejectonRatio( void );
+F32 getTankFillRORejectionRatio( void );
+F32 getRORRAverage( void );
+F32 getTankFillRORRAverage( void );
 
-BOOL testConductivitySensorDataPublishIntervalOverride( MESSAGE_T *message );
+BOOL testDDConductivitySensorDataPublishIntervalOverride( MESSAGE_T *message );
+BOOL testDDConductivitySensorFilteredReadingsOverride( MESSAGE_T *message );
+BOOL testDDConductivitySensorFilteredTemperatureReadingsOverride( MESSAGE_T *message );
+BOOL testFPConductivitySensorDataPublishIntervalOverride( MESSAGE_T *message );
+BOOL testFPConductivitySensorFilteredReadingsOverride( MESSAGE_T *message );
+BOOL testFPConductivitySensorFilteredTemperatureReadingsOverride( MESSAGE_T *message );
+BOOL testRORejectionRatioDataPublishIntervalOverride( MESSAGE_T *message );
+BOOL testRORejectionRatioFilteredOverride( MESSAGE_T *message );
+BOOL testConductivitySensorReadingsOverride( MESSAGE_T *message );
+BOOL testConductivitySensorTemperatureOverride( MESSAGE_T *message );
 
 /**@}*/