Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -rb9300084966f27ebd166962121c5217f5cd30eb0 -rf9570a9717805d0759622da836a33ee04f3fa40f
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision b9300084966f27ebd166962121c5217f5cd30eb0)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision f9570a9717805d0759622da836a33ee04f3fa40f)
@@ -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.
@@ -63,7 +64,7 @@
 static F32 dilutionLevelPct = 0.0;                                                                       ///< Reservoir dilution level.
 static DG_OP_MODE_T dgOpMode = DG_MODE_INIT;                                                             ///< DG operation mode.
 static U32 dgSubMode = 0;                                                                                ///< DG operation submode.
-static U32 timeReservoirInUseMS = 0;                                                                     ///< Reservoir time in use in milliseconds.
+static U32 timeReservoirInUse = 0;                                                                     ///< Reservoir time in use in milliseconds.
 static F32 volSpentUFML = 0.0;                                                                           ///< Ultrafiltration volume in milliliters.
 static DG_RESERVOIR_ID_T activeReservoir;                                                                ///< Active reservoir.
 static F32 recirculationLevelPct = 0.0;                                                                  ///< Recirculation level in percent.
@@ -105,7 +106,7 @@
  * @details Inputs: none
  * @details Outputs: reservoirsState, timeStartMS, timeDepletionMS, volTotalMl,
  * volSpentMl, reservoirsPublicationCounter, dilutionLevelPct, dgOpMode, dgSubMode,
- * timeReservoirInUseMS, volSpentUFML, activeReservoir, recirculationLevelPct,
+ * timeReservoirInUse, volSpentUFML, activeReservoir, recirculationLevelPct,
  * reservoirSwitchStartTimeMS, timeWaitToFillMS, targetFillFlowLPM, ratios
  * previousDialysateFlowRate
  * @return none
@@ -121,7 +122,7 @@
     dilutionLevelPct            = 0.0;
     dgOpMode                    = DG_MODE_INIT;
     dgSubMode                   = 0;
-    timeReservoirInUseMS        = 0;
+    timeReservoirInUse          = 0;
     volSpentUFML                = 0.0;
     activeReservoir             = DG_RESERVOIR_1;
     recirculationLevelPct       = 0.0;
@@ -174,7 +175,14 @@
     if ( ( TREATMENT_DIALYSIS_STATE == getTreatmentState() ) && ( getDialysisState() != DIALYSIS_SALINE_BOLUS_STATE ) )
     {
         volSpentML += ( flowRateMLPerMS * msSinceLastVolumeCalc );
+
+        if ( TREATMENT_DIALYSIS_STATE == getTreatmentState())
+        {
+
+            ++timeReservoirInUse;
+        }
     }
+
     // Update the reservoir start time
     timeStartMS = getMSTimerCount();
 
@@ -240,13 +248,13 @@
 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 ( timeReservoirInUse >= 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, (timeReservoirInUse * TASK_GENERAL_INTERVAL) )
         }
     }
 }
@@ -655,7 +663,7 @@
         setFinalReservoirVolume();
 
         // Switched the active reservoir so reset the reservoir in use timer
-        timeReservoirInUseMS = getMSTimerCount();
+        timeReservoirInUse = 0;
 
         // Reset to start state to restart drain, fill, switch process.
         state = TREATMENT_RESERVOIR_MGMT_START_STATE;