Index: firmware/App/Modes/ModeChemicalDisinfect.c
===================================================================
diff -u -rd0536d759cb33f099357033c3429401ff1637d26 -r798037378b180e53fc60846efac4ee8eea3c77be
--- firmware/App/Modes/ModeChemicalDisinfect.c	(.../ModeChemicalDisinfect.c)	(revision d0536d759cb33f099357033c3429401ff1637d26)
+++ firmware/App/Modes/ModeChemicalDisinfect.c	(.../ModeChemicalDisinfect.c)	(revision 798037378b180e53fc60846efac4ee8eea3c77be)
@@ -80,7 +80,9 @@
 #define RSRVRS_PARTIAL_FILL_UP_TIMEOUT_MS           ( 7 * SEC_PER_MIN * MS_PER_SECOND )                        ///< Reservoirs 1 & 2 partial fill up timeout in ms.
 #define RSRVRS_ALMOST_FULL_FILL_UP_TIMEOUT_MS       ( 1 * SEC_PER_MIN * MS_PER_SECOND )                        ///< Reservoirs 1 & 2 partial fill up timeout in ms. It is assumed the reservoir is nearly full to begin.
 #define RESERVOIR_MINIMUM_FULL_VOLUME_ML            1850.0F                                                    ///< When filling the reservoir, the volume reading must be at least this value before checking for the volume to level off.
-#define RSRVRS_FILL_TO_FULL_STABLE_TASK_INT         ( ( 2 * MS_PER_SECOND ) / TASK_GENERAL_INTERVAL )          ///< Reservoirs 1 & 2 full stable time in task intervals.
+#define RSRVRS_STEADY_STATE_MAX_VOL_CHANGE_ML       5.0F                                                       ///< Reservoirs steady state maximum volume change in milliliters.
+#define RSRVRS_FULL_STATUS_CHECK_TIME_INTERVAL_MS   ( 1 * MS_PER_SECOND )                                      ///< Reservoirs full status check time interval in milliseconds.
+#define RSRVRS_FILL_TO_FULL_STABLE_TASK_INT         4                                                          ///< Reservoirs 1 & 2 full stable time in task intervals.
 
 // Prime acid line state defines
 #define PRIME_ACID_LINE_TIMEOUT_MS                  ( 2 * SEC_PER_MIN * MS_PER_SECOND )                        ///< Priming acid line timeout in milliseconds.
@@ -153,6 +155,14 @@
     U32 acidCondSamplesNextIndex;                                                                              ///< Acid conductivity sample next index number.
 } ACID_DATA_STATUS_T;
 
+/// Reservoir full data structure
+typedef struct
+{
+    F32 prevRsrvrVolumeML[ NUM_OF_DG_RESERVOIRS ];                                                             ///< Previous reservoir volumes in milliliters.
+    U32 startTimeStampMS;                                                                                      ///< Start time stamp in milliseconds.
+    BOOL hasTimeStampBeenSet;                                                                                  ///< Boolean flag to indicate that the timer has been set or not.
+} RSRVR_FULL_STATUS_T;
+
 // ********** private data **********
 
 static DG_CHEM_DISINFECT_STATE_T chemDisinfectState;                                                           ///< Currently active chemical disinfect state.
@@ -185,6 +195,7 @@
 static U32 maxTemperatureOutOfRangeStartTimeMS;                                                                ///< Maximum temperature out of range start time in milliseconds.
 static U32 maxCondOutOfRangeStartTimeMS;                                                                       ///< Maximum conductivity out of range start time in milliseconds.
 static ACID_DATA_STATUS_T acidDataStatus;                                                                      ///< Acid data status.
+static RSRVR_FULL_STATUS_T rsrvrFullStatus;                                                                    ///< Reservoir full status.
 
 #ifndef _RELEASE_
 /* Nelson Labs is in charge of testing the efficacy of the disinfects (heat and chem). The codes that contain the name Nelson are used to
@@ -248,6 +259,7 @@
  * rsrvrFillToFullStableTimeCounter, R2FullVolume, disinfectantMixRatio,
  * haveDrainParamsBeenInit[ DG_RESERVOIR_1 ], haveDrainParamsBeenInit[ DG_RESERVOIR_2 ],
  * maxTemperatureOutOfRangeStartTimeMS, maxCondOutOfRangeStartTimeMS,
+ * rsrvrFullStatus
  * @return none
  *************************************************************************/
 void initChemicalDisinfectMode( void )
@@ -295,8 +307,11 @@
     acidDataStatus.acidDataColHasTimerBeenSet  = getMSTimerCount();
     acidDataStatus.acidCondRunningSumUSPCM     = 0.0F;
     acidDataStatus.acidCondSamplesNextIndex    = 0;
+    rsrvrFullStatus.hasTimeStampBeenSet        = FALSE;
+    rsrvrFullStatus.startTimeStampMS           = getMSTimerCount();
 
     memset( acidDataStatus.acidCondSamplesUSPCM, 0x0, sizeof( F32 ) * ACID_MOVING_AVG_NUM_OF_SAMPLES );
+    memset( rsrvrFullStatus.prevRsrvrVolumeML, 0.0F, sizeof( F32 ) * NUM_OF_DG_RESERVOIRS );
 
 #ifndef _RELEASE_
     setNelsonSupportConditions();
@@ -1451,39 +1466,63 @@
 static DG_RESERVOIR_STATUS_T getRsrvrFillToFullStatus( DG_RESERVOIR_ID_T r, U32 timeout )
 {
     DG_RESERVOIR_STATUS_T status = DG_RESERVOIR_BELOW_TARGET;
-    F32 currentVolume            = 0.0F;
+    F32 currentVolumeML          = 0.0F;
 
-    if ( DG_RESERVOIR_1 == r )
+    switch( r )
     {
-        currentVolume  = getLoadCellSmallFilteredWeight( LOAD_CELL_RESERVOIR_1_PRIMARY );
+        case DG_RESERVOIR_1:
+            currentVolumeML = getLoadCellSmallFilteredWeight( LOAD_CELL_RESERVOIR_1_PRIMARY );
+            break;
+
+        case DG_RESERVOIR_2:
+            currentVolumeML = getLoadCellSmallFilteredWeight( LOAD_CELL_RESERVOIR_2_PRIMARY );
+            break;
+
+        default:
+            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, SW_FAULT_ID_INVALID_DG_RESERVOIR_SELECTED, r )
+            break;
     }
-    else if ( DG_RESERVOIR_2 == r )
-    {
-        currentVolume  = getLoadCellSmallFilteredWeight( LOAD_CELL_RESERVOIR_2_PRIMARY );
-    }
-    else
-    {
-        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, SW_FAULT_ID_INVALID_DG_RESERVOIR_SELECTED, r )
-    }
 
     // Check the volume of the reservoir against the long term filtered volume
-    if ( currentVolume > RESERVOIR_MINIMUM_FULL_VOLUME_ML )
+    if ( currentVolumeML > RESERVOIR_MINIMUM_FULL_VOLUME_ML )
     {
-        if ( ++rsrvrFillToFullStableTimeCounter >= RSRVRS_FILL_TO_FULL_STABLE_TASK_INT )
+        if ( FALSE == rsrvrFullStatus.hasTimeStampBeenSet )
         {
-            status = DG_RESERVOIR_REACHED_TARGET;
-            rsrvrFillToFullStableTimeCounter = 0;
+            rsrvrFullStatus.startTimeStampMS    = getMSTimerCount();
+            rsrvrFullStatus.hasTimeStampBeenSet = TRUE;
+        }
+        else if ( TRUE == didTimeout( rsrvrFullStatus.startTimeStampMS, RSRVRS_FULL_STATUS_CHECK_TIME_INTERVAL_MS ) )
+        {
+            if ( fabs( currentVolumeML - rsrvrFullStatus.prevRsrvrVolumeML[ r ] ) < RSRVRS_STEADY_STATE_MAX_VOL_CHANGE_ML )
+            {
+                rsrvrFillToFullStableTimeCounter++;
+            }
+            else
+            {
+                rsrvrFillToFullStableTimeCounter = 0;
+            }
+
+            rsrvrFullStatus.prevRsrvrVolumeML[ r ] = currentVolumeML;
+            rsrvrFullStatus.hasTimeStampBeenSet    = FALSE;
+        }
+
+        if ( rsrvrFillToFullStableTimeCounter > RSRVRS_FILL_TO_FULL_STABLE_TASK_INT )
+        {
+            status                                 = DG_RESERVOIR_REACHED_TARGET;
+            rsrvrFillToFullStableTimeCounter       = 0;
+            // Set the state timer in case it needs to be used for another timeout check
+            stateTimer                             = getMSTimerCount();
+            rsrvrFullStatus.prevRsrvrVolumeML[ r ] = 0.0F;
+
             // Record the full volumes
             if ( DG_RESERVOIR_1 == r )
             {
-                R1FullVolume = currentVolume;
+                R1FullVolume = currentVolumeML;
             }
             else if ( DG_RESERVOIR_2 == r )
             {
-                R2FullVolume = currentVolume;
+                R2FullVolume = currentVolumeML;
             }
-            // Set the state timer in case it needs to be used for another timeout check
-            stateTimer = getMSTimerCount();
         }
     }
     else if ( TRUE == didTimeout( stateTimer, timeout ) )