Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -r5b448e81db260e5b041699a83c6f2a3faa260ea9 -r7498c77e7f99c2d3854df69f1999244de066a504
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 5b448e81db260e5b041699a83c6f2a3faa260ea9)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 7498c77e7f99c2d3854df69f1999244de066a504)
@@ -18,15 +18,16 @@
 
 // ********** private definitions **********
 
-#define RESERVOIR_SETTLE_TIME_MS                          5000                                           ///< Allocated time to settle the filled reservoir in milliseconds.
-#define RESERVOIR_CYCLE_EXTRA_MARGIN_TIME_MS              8000                                           ///< Reservoir extra time in during the cycle for error in milliseconds.
+#define RESERVOIR_SETTLE_TIME_MS                          5000                                                          ///< Allocated time to settle the filled reservoir in milliseconds.
+#define RESERVOIR_CYCLE_EXTRA_MARGIN_TIME_MS              8000                                                          ///< Reservoir extra time in during the cycle for error in milliseconds.
 
 #define MAX_RESERVOIR_VOLUME_ML                           1950.0                                         ///< Maximum allowed fluid in a reservoir in milliliters.
 #define MAX_RESERVOIR_DILUTION                            0.15F                                          ///< Maximum reservoir dilution limit.
 #define MAX_RESERVOIR_RECIRCULATION                       1.1F                                           ///< Maximum reservoir recirculation limit.
 
-#define MAX_RESERVOIR_DEPLETION_TIME_MS                   ( 30 * SEC_PER_MIN * MS_PER_SECOND )           ///< Maximum allowed depletion time in milliseconds.
-#define RESERVOIR_DATA_PUB_INTERVAL                       ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )      ///< Interval (ms/task time) at which the reservoir data is published on the CAN bus.
+#define MAX_RESERVOIR_DEPLETION_TIME_MS                   ( 30 * SEC_PER_MIN * MS_PER_SECOND )                          ///< Maximum allowed depletion time in milliseconds.
+#define RESERVOIR_DATA_PUB_INTERVAL                       ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )                     ///< Interval (ms/task time) at which the reservoir data is published on the CAN bus.
+#define RESERVOIR_DEPLETION_INTERVAL                      ( MAX_RESERVOIR_DEPLETION_TIME_MS / TASK_GENERAL_INTERVAL )   ///< Interval (ms/task time) for maximum allowed depletion time.
 
 #define DIALYSATE_FLOW_RATE_350_ML_PER_MIN                0.35F                                          ///< Dialysate flow rate 350 mL/min.
 #define DIALYSATE_FLOW_RATE_400_ML_PER_MIN                0.4F                                           ///< Dialysate flow rate 400 mL/min.
@@ -39,6 +40,10 @@
 #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 DIA_FLOW_TO_FILL_FLOW_SECOND_ORDER_COEFF          10.0                                                          ///< Dialysate flow rate to fill flow rate second order coefficient.
+#define DIA_FLOW_TO_FILL_FLOW_FIRST_ORDER_COEFF           7.5                                                           ///< Dialysate flow rate to fill flow rate first order coefficient.
+#define DIA_FLOW_TO_FILL_FLOW_CONSTANT                    2.0                                                           ///< Dialysate flow rate to fill flow rate constant.
+
 // ********** private data **********
 
 /// States of the treatment reservoir management state machine.
@@ -174,7 +179,13 @@
     if (  getSalineBolusState() != SALINE_BOLUS_STATE_IN_PROGRESS )
     {
         volSpentML += ( flowRateMLPerMS * msSinceLastVolumeCalc );
+
+        if ( TREATMENT_DIALYSIS_STATE == getTreatmentState())
+        {
+            ++timeReservoirInUseMS;
+        }
     }
+
     // Update the reservoir start time
     timeStartMS = getMSTimerCount();
 
@@ -240,13 +251,13 @@
 static void checkReservoirDepletionTime( void )
 {
     // Check if the time that the reservoir has been use has exceeded the limit
-    if ( TRUE == didTimeout( timeReservoirInUseMS, MAX_RESERVOIR_DEPLETION_TIME_MS ) )
+    if ( timeReservoirInUseMS >= RESERVOIR_DEPLETION_INTERVAL )
     {
 #ifndef _RELEASE_
         if ( getSoftwareConfigStatus( SW_CONFIG_DISABLE_RESERVOIRS_ALARMS ) != SW_CONFIG_ENABLE_VALUE )
 #endif
         {
-            SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_ACTIVE_RESERVOIR_DEPLETION_TIME_OUT, calcTimeSince( timeReservoirInUseMS ) )
+            SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_ACTIVE_RESERVOIR_DEPLETION_TIME_OUT, timeReservoirInUseMS )
         }
     }
 }
@@ -651,7 +662,7 @@
         setFinalReservoirVolume();
 
         // Switched the active reservoir so reset the reservoir in use timer
-        timeReservoirInUseMS = getMSTimerCount();
+        timeReservoirInUseMS = 0;
 
         // Reset to start state to restart drain, fill, switch process.
         state = TREATMENT_RESERVOIR_MGMT_START_STATE;