Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r50086215a9c8977c977f836dcd4c454dd4d7d712 -ra657feb0cc008fa976753323207327ddd02d4f2b
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 50086215a9c8977c977f836dcd4c454dd4d7d712)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision a657feb0cc008fa976753323207327ddd02d4f2b)
@@ -8,7 +8,7 @@
 * @file    ModePreTreat.c
 *
 * @author  (last)      Sean Nash
-* @date    (last)      31-Jan-2023
+* @date    (last)      08-Feb-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -1206,8 +1206,6 @@
         }
         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 )
             {
@@ -1217,10 +1215,6 @@
                     reservoirStatus[ inactiveReservoir ].flushComplete = TRUE;
                 }
             }
-
-            rsrvrCmd.reservoirID                     = (U32)activeReservoir;
-            rsrvrCmd.useLastTrimmerHeaterDC          = FALSE;
-            cmdSetDGActiveReservoir( &rsrvrCmd );
         }
     }
 
@@ -1240,17 +1234,38 @@
     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 ) &&
+                   ( getPrimeState() < HD_PRIME_PAUSE ) ) )
+            {
+                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;