Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r4068c609827d855903b352c399b204bbb17ae12f -reca2f2bf62570bb920d0890b7fc53e9d0ccfed9d
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 4068c609827d855903b352c399b204bbb17ae12f)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision eca2f2bf62570bb920d0890b7fc53e9d0ccfed9d)
@@ -1084,26 +1084,27 @@
     DG_OP_MODE_T dgOpMode = getDGOpMode();
     U32 dgSubMode = getDGSubMode();
     U32 volume = 0;
-    DG_RESERVOIR_ID_T activeReservoir = getDGActiveReservoir();
+    DG_RESERVOIR_ID_T inactiveReservoir = getDGInactiveReservoir();
 
     if ( ( DG_MODE_GENE == dgOpMode ) && ( DG_GEN_IDLE_MODE_STATE_FLUSH_WATER == dgSubMode ) )
     {
         // Drain both reservoirs and return to active res 2 before initial fills
-        if ( reservoirStatus[ activeReservoir ].initialDrain != TRUE )
+        if ( reservoirStatus[ inactiveReservoir ].initialDrain != TRUE )
         {
-            reservoirStatus[ activeReservoir ].initialDrain = TRUE;
+            reservoirStatus[ inactiveReservoir ].initialDrain = TRUE;
             state = PRE_TREATMENT_RESERVOIR_MGMT_REQUEST_RESERVOIR_SWITCH_STATE;
         }
 
         // Once both reservoirs drained and returned to active res 2, wait for pre-tx workflow
         //  to get to point where fills are allowed, before starting fill
         // not flushed and need to fill -OR-
         // flushed and need to fill after entering dry self test state
-        else if ( ( TRUE == reservoirStatus[ activeReservoir ].startFlushFill ) ||
-                  ( ( TRUE == reservoirStatus[ activeReservoir ].startNormalFill ) &&
+        else if ( ( TRUE == reservoirStatus[ inactiveReservoir ].startFlushFill ) ||
+                  ( ( TRUE == reservoirStatus[ inactiveReservoir ].startNormalFill ) &&
                     ( currentPreTreatmentState >= HD_PRE_TREATMENT_SELF_TEST_DRY_STATE ) ) )
         {
-            volume = getPreTreatmentFillVolume( activeReservoir );
+            volume = getPreTreatmentFillVolume( inactiveReservoir );
+
             cmdStartDGFill( volume, DEFAULT_TARGET_FILL_FLOW_RATE_LPM );
             state = PRE_TREATMENT_RESERVOIR_MGMT_FILL_CMD_RESP_STATE;
         }