Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -re5d6674fbf4b6ddd8057385babac0a085ce18f42 -r05b346d3ce9a787d845a6358a9a0ac338e6d1a82
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision e5d6674fbf4b6ddd8057385babac0a085ce18f42)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 05b346d3ce9a787d845a6358a9a0ac338e6d1a82)
@@ -1207,8 +1207,6 @@
         }
         else
         {
-            DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
-
             // Start tracking flush cycles, flushComplete => don't drain again, this completes the final fill.
             if ( FALSE == reservoirStatus[ inactiveReservoir ].flushComplete )
             {
@@ -1218,10 +1216,6 @@
                     reservoirStatus[ inactiveReservoir ].flushComplete = TRUE;
                 }
             }
-
-            rsrvrCmd.reservoirID                     = (U32)activeReservoir;
-            rsrvrCmd.useLastTrimmerHeaterDC          = FALSE;
-            cmdSetDGActiveReservoir( &rsrvrCmd );
         }
     }
 
@@ -1241,17 +1235,37 @@
     PRE_TREATMENT_RESERVOIR_MGMT_STATE_T state = PRE_TREATMENT_RESERVOIR_MGMT_REQUEST_RESERVOIR_SWITCH_STATE;
     DG_OP_MODE_T dgOpMode = getDGOpMode();
     U32 dgSubMode = getDGSubMode();
-    DG_RESERVOIR_ID_T inactiveReservoir = getDGInactiveReservoir();
 
     //wait after drain or fill
     if ( ( DG_MODE_GENE == dgOpMode ) && ( DG_GEN_IDLE_MODE_STATE_FLUSH_WATER == dgSubMode ) )
     {
-        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+        BOOL waitBeforeSwitch = TRUE;
 
-        rsrvrCmd.reservoirID            = (U32)inactiveReservoir;
-        rsrvrCmd.useLastTrimmerHeaterDC = TRUE;
-        state                           = PRE_TREATMENT_RESERVOIR_MGMT_WAIT_FOR_RESERVOIR_SWITCH_STATE;
-        cmdSetDGActiveReservoir( &rsrvrCmd );
+        // We do not want to switch over to res 2 final fill until prime is ready for it.
+        if ( TRUE == reservoirStatus[ DG_RESERVOIR_2 ].fillComplete )
+        {
+            if ( ( getPreTreatmentSubState() > HD_PRE_TREATMENT_PRIME_STATE ) ||
+                 ( ( HD_PRE_TREATMENT_PRIME_STATE == getPreTreatmentSubState() ) &&
+                   ( getPrimeState() >= HD_PRIME_RESERVOIR_TWO_FILL_COMPLETE_STATE ) ) )
+            {
+                waitBeforeSwitch = FALSE;
+            }
+        }
+        else
+        {
+            waitBeforeSwitch = FALSE;
+        }
+
+        if ( waitBeforeSwitch != TRUE )
+        {
+            DG_RESERVOIR_ID_T inactiveReservoir = getDGInactiveReservoir();
+            DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
+            rsrvrCmd.reservoirID            = (U32)inactiveReservoir;
+            rsrvrCmd.useLastTrimmerHeaterDC = TRUE;
+            state                           = PRE_TREATMENT_RESERVOIR_MGMT_WAIT_FOR_RESERVOIR_SWITCH_STATE;
+            cmdSetDGActiveReservoir( &rsrvrCmd );
+        }
     }
 
     return state;