Index: firmware/App/Controllers/DGInterface.c
===================================================================
diff -u -ra56db4650fe5652d633e0c51b29da32d5d708608 -r9b6d9a0db373b39c3d04dd07516fde59b292bbc5
--- firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision a56db4650fe5652d633e0c51b29da32d5d708608)
+++ firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision 9b6d9a0db373b39c3d04dd07516fde59b292bbc5)
@@ -967,6 +967,21 @@
 
 /*********************************************************************//**
  * @brief
+ * The cmdDGParkConcentratePumps function sends a park concentrate pumps command
+ * message to the DG.
+ * @details Inputs: none
+ * @details Outputs: park concentrate pumps command sent to DG.
+ * @return none
+ *************************************************************************/
+void cmdDGParkConcentratePumps( void )
+{
+    dgCmdResp[ DG_CMD_PARK_CONCENTRATE_PUMPS ].commandID = DG_CMD_NONE;
+
+    sendDGParkConcentratePumpsCommand( );
+}
+
+/*********************************************************************//**
+ * @brief
  * The cmdStartDGFlush function sends a start flush command message to
  * the DG.
  * @details Inputs: none
Index: firmware/App/Controllers/DGInterface.h
===================================================================
diff -u -rf1157c760b320bf088921a25eb78e973d6341578 -r9b6d9a0db373b39c3d04dd07516fde59b292bbc5
--- firmware/App/Controllers/DGInterface.h	(.../DGInterface.h)	(revision f1157c760b320bf088921a25eb78e973d6341578)
+++ firmware/App/Controllers/DGInterface.h	(.../DGInterface.h)	(revision 9b6d9a0db373b39c3d04dd07516fde59b292bbc5)
@@ -147,6 +147,7 @@
 void cmdStopDGTrimmerHeater( void );
 void cmdDGSampleWater( SAMPLE_WATER_CMD_T cmd );
 void cmdStartDGFlush( void );
+void cmdDGParkConcentratePumps( void );
 void cmdStopDGFlush( void );
 void cmdStartDGHeatDisinfect( void );
 void cmdStopDGHeatDisinfect( void );
Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r526e890e4e35fac0a622af538bf611ea15a30609 -r9b6d9a0db373b39c3d04dd07516fde59b292bbc5
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 526e890e4e35fac0a622af538bf611ea15a30609)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 9b6d9a0db373b39c3d04dd07516fde59b292bbc5)
@@ -1527,6 +1527,9 @@
 
                 // Set the heating parameters
                 setPreTreatmentHeatingParams( targetTempC, FILL_RESERVOIR_TO_VOLUME_ML, DEFAULT_TARGET_FILL_FLOW_RATE_LPM, dialysateFlowMLPM );
+                // after reservoir fill at end of the pre-treatment, do park the concentrate pumps to maintain conductivity
+                // when treatment begins
+                cmdDGParkConcentratePumps();
                 state = PRE_TREATMENT_RESERVOIR_MGMT_COMPLETE_STATE;
             }
             else
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r0826b00090b65c16a3e52e006cc3c016a6bf6a08 -r9b6d9a0db373b39c3d04dd07516fde59b292bbc5
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 0826b00090b65c16a3e52e006cc3c016a6bf6a08)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 9b6d9a0db373b39c3d04dd07516fde59b292bbc5)
@@ -1719,6 +1719,30 @@
 
 /*********************************************************************//**
  * @brief
+ * The sendDGParkConcentratePumpsCommand function constructs a DG concetentrate
+ * pumps park request msg to the DG and queues the msg for transmit on the appropriate CAN channel.
+ * @details Inputs: none
+ * @details Outputs: DG park concentrate pumps command msg constructed and queued..
+ * @return TRUE if msg successfully queued for transmit, FALSE if not
+ *************************************************************************/
+BOOL sendDGParkConcentratePumpsCommand( void )
+{
+    BOOL result;
+    MESSAGE_T msg;
+
+    // Create a message record
+    blankMessage( &msg );
+    msg.hdr.msgID = MSG_ID_DG_PARK_CONCENTRATE_PUMPS;
+    msg.hdr.payloadLen = 0;
+
+    // Serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
+    result = serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_DG, ACK_REQUIRED );
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The sendDGStartFlushModeCommand function constructs a DG start/stop
  * flush mode command message and queues the msg for transmit on the
  * appropriate CAN channel.
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -r0826b00090b65c16a3e52e006cc3c016a6bf6a08 -r9b6d9a0db373b39c3d04dd07516fde59b292bbc5
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 0826b00090b65c16a3e52e006cc3c016a6bf6a08)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 9b6d9a0db373b39c3d04dd07516fde59b292bbc5)
@@ -473,6 +473,9 @@
 // MSG_ID_DG_START_STOP_FLUSH
 BOOL sendDGStartFlushModeCommand( BOOL start );
 
+// MSG_ID_DG_PARK_CONCENTRATE_PUMPS
+BOOL sendDGParkConcentratePumpsCommand( void );
+
 // MSG_ID_DG_START_STOP_HEAT_DISINFECT
 BOOL sendDGStartHeatDisinfectModeCommand( BOOL start );