Index: firmware/App/Modes/ModeFill.c
===================================================================
diff -u -r2fea76e972a450a97c74b2a9f627095032a3b586 -r484b185f0cf4b2ea0ba9de331573952b1b5124b4
--- firmware/App/Modes/ModeFill.c	(.../ModeFill.c)	(revision 2fea76e972a450a97c74b2a9f627095032a3b586)
+++ firmware/App/Modes/ModeFill.c	(.../ModeFill.c)	(revision 484b185f0cf4b2ea0ba9de331573952b1b5124b4)
@@ -25,6 +25,7 @@
 #include "Pressures.h"
 #include "Reservoirs.h"
 #include "ROPump.h"
+#include "TaskGeneral.h"
 #include "TemperatureSensors.h"
 #include "Timers.h"
 #include "Valves.h"
@@ -47,10 +48,18 @@
 
 #define DIALYSATE_FILL_TIME_OUT                         ( 5 * SEC_PER_MIN * MS_PER_SECOND )         ///< Time out period when reservoir is not filled with correct dialysate.
 
+#define ACID_BICARB_CONCENTRATE_ADDITION_MULTIPLER      1.06                                        ///< Acid and bicarbonate concentrates make up around 6% to total volume.
+#define FLOW_INTEGRATED_VOLUME_CHECK_TOLERANCE          0.1                                         ///< Flow integrated volume has 10% tolerance compare to load cell reading.
+
+/// Multiplier to conver flow (mL/min) into volume (mL) for period of general task interval.
+static const F32 RO_FLOW_INTEGRATOR = ( ( ML_PER_LITER * TASK_GENERAL_INTERVAL ) / ( SEC_PER_MIN * MS_PER_SECOND ) );
+
 // ********** private data **********
 
-static DG_FILL_MODE_STATE_T fillState;                                                              ///< Currently active fill state.
-static U32 dialysateFillStartTime;                                                                  ///< Current time when starting to fill dialysate.
+static DG_FILL_MODE_STATE_T fillState;                  ///< Currently active fill state.
+static U32 dialysateFillStartTime;                      ///< Current time when starting to fill dialysate.
+static F32 reservoirBaseWeight;                         ///< Fill reservoir base weight.
+static F32 totalROFlowRate;                             ///< Total RO flow rate over period of time.
 
 // ********** private function prototypes **********
 
@@ -83,6 +92,8 @@
 {
     fillState = DG_FILL_MODE_STATE_START;
     dialysateFillStartTime = getMSTimerCount();
+    reservoirBaseWeight = 0.0;
+    totalROFlowRate = 0.0;
 
     // set initial actuator states
     setValveState( VDR, VALVE_STATE_DRAIN_C_TO_NO );
@@ -149,6 +160,7 @@
 static DG_FILL_MODE_STATE_T handleCheckInletWaterState( void )
 {
     DG_FILL_MODE_STATE_T result = DG_FILL_MODE_STATE_CHECK_INLET_WATER;
+    DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
 
     BOOL const isWaterTemperatureGood  = !isAlarmActive( ALARM_ID_INLET_WATER_HIGH_TEMPERATURE ) && !isAlarmActive( ALARM_ID_INLET_WATER_LOW_TEMPERATURE );
     BOOL const isWaterConductivityGood = !isAlarmActive( ALARM_ID_INLET_WATER_HIGH_CONDUCTIVITY ) && !isAlarmActive( ALARM_ID_INLET_WATER_LOW_CONDUCTIVITY ) &&
@@ -162,6 +174,8 @@
 
     if ( isInletWaterReady )
     {
+        reservoirBaseWeight = getReservoirWeight( inactiveReservoir );
+
         // Concentrate pumps on request and set RO pump to flow rate 800 mL/min
         requestConcentratePumpsOn( CONCENTRATEPUMPS_CP1 );
         requestConcentratePumpsOn( CONCENTRATEPUMPS_CP2 );
@@ -216,11 +230,13 @@
 static DG_FILL_MODE_STATE_T handleDeliverDialysateState( void )
 {
     DG_FILL_MODE_STATE_T result = DG_FILL_MODE_STATE_DELIVER_DIALYSATE;
-    RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
+    DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
 
     handleDialysateMixing();
     checkConcentrateConductivity();
 
+    totalROFlowRate += getMeasuredROFlowRate();
+
     BOOL isDialysateConductivityBad = ( isAlarmActive( ALARM_ID_POST_ACID_CONDUCTIVITY_OUT_OF_RANGE ) || isAlarmActive( ALARM_ID_POST_BICARB_CONDUCTIVITY_OUT_OF_RANGE ) );
 
 #ifdef DISABLE_DIALYSATE_CHECK
@@ -237,6 +253,15 @@
     // if we've reached our target fill to volume (by weight), we're done filling - go back to re-circ mode
     if ( hasTargetFillVolumeBeenReached( inactiveReservoir ) )
     {
+        F32 const filledWeight = getReservoirWeight( inactiveReservoir ) - reservoirBaseWeight;
+        F32 const integratedVolume = totalROFlowRate * RO_FLOW_INTEGRATOR * ACID_BICARB_CONCENTRATE_ADDITION_MULTIPLER;
+        F32 const integratedVolumeToLoadCellReadingPercent = 1 - ( filledWeight / integratedVolume );
+
+        if ( integratedVolumeToLoadCellReadingPercent > FLOW_INTEGRATED_VOLUME_CHECK_TOLERANCE )
+        {
+            SET_ALARM_WITH_2_F32_DATA( ALARM_ID_DG_FLOW_METER_CHECK_FAILURE, filledWeight, integratedVolume );
+        }
+
         requestConcentratePumpsOff( CONCENTRATEPUMPS_CP1 );
         requestConcentratePumpsOff( CONCENTRATEPUMPS_CP2 );
         requestNewOperationMode( DG_MODE_CIRC );