Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -rad4d98e7d69ee6320a7ab573c353cd6ff92a76fe -rb9300084966f27ebd166962121c5217f5cd30eb0
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision ad4d98e7d69ee6320a7ab573c353cd6ff92a76fe)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision b9300084966f27ebd166962121c5217f5cd30eb0)
@@ -39,6 +39,8 @@
 #define DIA_FLOW_TO_FILL_FLOW_FIRST_ORDER_COEFF           7.5F                                           ///< Dialysate flow rate to fill flow rate first order coefficient.
 #define DIA_FLOW_TO_FILL_FLOW_CONSTANT                    2.0F                                           ///< Dialysate flow rate to fill flow rate constant.
 
+#define MAX_RESERVOIR_VOL_BEFORE_SWITCH_ML                1900.0F                                        ///< Maximum reservoir volume before we switch reservoirs (in mL).
+
 // ********** private data **********
 
 /// States of the treatment reservoir management state machine.
@@ -513,9 +515,7 @@
         timeWaitToFillMS = timeDepleteMS - ( getFillTimeMS() + RESERVOIR_SETTLE_TIME_MS + RESERVOIR_CYCLE_EXTRA_MARGIN_TIME_MS );
 
         // If the wait time has elapsed, trigger a fill command
-        // TODO uncomment
-        //if ( timeWaitToFillMS <= 0 )
-        // TODO uncomment
+        if ( timeWaitToFillMS <= 0 )
         {
             cmdStartDGFill( FILL_RESERVOIR_TO_VOLUME_ML, targetFillFlowRateLPM );
         }
@@ -587,10 +587,16 @@
 static TREATMENT_RESERVOIR_MGMT_STATE_T handleReservoirMgmtWaitForFillSettleState( void )
 {
     TREATMENT_RESERVOIR_MGMT_STATE_T state = TREATMENT_RESERVOIR_MGMT_WAIT_FOR_FILL_SETTLE_STATE;
+    DG_RESERVOIR_ID_T active = getDGActiveReservoir();
 
+    // Get the ultra-filtration volume milliliters
+    // Get the dilution level in percent = spent ultra-filtration volume / target fill volume in milliliters
+    volSpentUFML     = getReservoirUltrafiltrationVol( activeReservoir );
+    dilutionLevelPct = volSpentUFML / (F32)FILL_RESERVOIR_TO_VOLUME_ML;
+
     // Wait for the reservoir to settle and then send the commands to switch the active reservoir     TODO - restore #define below
     if ( ( TRUE == didTimeout( reservoirSwitchStartTimeMS, 15000 /*RESERVOIR_SETTLE_TIME_MS*/ ) ) &&
-         ( ( dilutionLevelPct >= MAX_RESERVOIR_DILUTION ) || ( volSpentML >= (F32)FILL_RESERVOIR_TO_VOLUME_ML ) ) )
+         ( ( dilutionLevelPct >= MAX_RESERVOIR_DILUTION ) || ( volSpentML >= (F32)FILL_RESERVOIR_TO_VOLUME_ML ) || ( getReservoirWeight( active ) > MAX_RESERVOIR_VOL_BEFORE_SWITCH_ML ) ) )
     {
         DG_RESERVOIR_ID_T inactiveRes = getDGInactiveReservoir();