Index: firmware/App/Controllers/SyringePump.c
===================================================================
diff -u -rfed8ef4f0540818dfb7ca670a65eac39c12cb25a -r0e457429d65039d16cd631c3aaa06b5409de67c4
--- firmware/App/Controllers/SyringePump.c	(.../SyringePump.c)	(revision fed8ef4f0540818dfb7ca670a65eac39c12cb25a)
+++ firmware/App/Controllers/SyringePump.c	(.../SyringePump.c)	(revision 0e457429d65039d16cd631c3aaa06b5409de67c4)
@@ -91,6 +91,8 @@
 #define SYRINGE_PUMP_DAC_VOLTAGE_MAX_ERROR            0.05F                                 ///< Force sensor POST check for DAC voltage - max delta.
 #define MIN_SYRINGE_PUMP_RATE_FOR_DIR_ALARM           0.5F                                  ///< Minimum measured rate (in mL/hr) required before enforcing direction alarm.
 
+/// HW volume variance in the syringe pump in mL.
+#define SYRINGE_PUMP_HW_TOLERANCE_ML                  0.65F
 /// HW volume variance in the syringe pump in encoder counts.
 #define SYRINGE_PUMP_HW_TOLERANCE_POS                 ( SYRINGE_ENCODER_COUNTS_PER_ML * SYRINGE_PUMP_HW_TOLERANCE_ML )
 /// Expected position of empty in relation to home position.
@@ -1463,11 +1465,11 @@
     U32  preStop  = getTreatmentParameterU32( TREATMENT_PARAM_HEPARIN_PRE_STOP_TIME );
     U32  setTxDur = getTreatmentParameterU32( TREATMENT_PARAM_TREATMENT_DURATION );
     F32  hepDurHr = ( (F32)( setTxDur - preStop ) / (F32)MIN_PER_HOUR );
-    F32  txVolumeReq = SYRINGE_PUMP_PRIME_VOLUME_ML + bolusVol + ( hepDurHr * contRate ) + SYRINGE_PUMP_HW_TOLERANCE_ML;
+    F32  txVolumeReq = SYRINGE_PUMP_PRIME_VOLUME_ML + bolusVol + ( hepDurHr * contRate );
     F32  syringeVol = ( SYRINGE_PUMP_EMPTY_POS - (F32)pos ) / SYRINGE_ENCODER_COUNTS_PER_ML;
 
-    syringePumpVolumeRequired = txVolumeReq;
-    txVolumeReq = txVolumeReq + SYRINGE_PUMP_PRELOAD_MARGIN_VOLUME_ML;
+    syringePumpVolumeRequired = txVolumeReq + SYRINGE_PUMP_FILL_VOLUME_OFFSET_ML;
+    txVolumeReq = txVolumeReq  + SYRINGE_PUMP_FILL_VOLUME_OFFSET_ML + SYRINGE_PUMP_PRELOAD_MARGIN_VOLUME_ML;
 
     // Handle ramp up
     rampSyringePump();
@@ -1831,11 +1833,9 @@
         syringePumpEmptyForceCount = 0;
     }
     // If near empty position, assume syringe is empty
-    // Check for force threshold within SYRINGE_PUMP_HW_TOLERANCE_POS of empty
-    if ( pos >= SYRINGE_PUMP_EMPTY_POS ||
-        ( syringePumpEmptyForceCount > SYRINGE_PUMP_EMPTY_FORCE_COUNT &&
-        ( pos <= ( SYRINGE_PUMP_EMPTY_POS + SYRINGE_PUMP_HW_TOLERANCE_POS ) ||
-          pos >= ( SYRINGE_PUMP_EMPTY_POS - SYRINGE_PUMP_HW_TOLERANCE_POS ) ) ) )
+    // Check for force threshold over some time and within SYRINGE_PUMP_HW_TOLERANCE_POS of empty
+    if ( ( pos >= SYRINGE_PUMP_EMPTY_POS ) ||
+       ( ( syringePumpEmptyForceCount >= SYRINGE_PUMP_EMPTY_FORCE_COUNT ) && ( pos >= ( SYRINGE_PUMP_EMPTY_POS - SYRINGE_PUMP_HW_TOLERANCE_POS ) ) ) )
     {
         heparinDeliveryState = HEPARIN_STATE_EMPTY;
         SET_ALARM_WITH_2_F32_DATA( ALARM_ID_HD_SYRINGE_PUMP_SYRINGE_EMPTY, (F32)pos, force )
Index: firmware/App/Controllers/SyringePump.h
===================================================================
diff -u -rfed8ef4f0540818dfb7ca670a65eac39c12cb25a -r0e457429d65039d16cd631c3aaa06b5409de67c4
--- firmware/App/Controllers/SyringePump.h	(.../SyringePump.h)	(revision fed8ef4f0540818dfb7ca670a65eac39c12cb25a)
+++ firmware/App/Controllers/SyringePump.h	(.../SyringePump.h)	(revision 0e457429d65039d16cd631c3aaa06b5409de67c4)
@@ -33,7 +33,7 @@
 // ********** public definitions **********
 
 #define SYRINGE_PUMP_PRIME_VOLUME_ML                  0.353F                                ///< Target syringe prime volume (in mL).
-#define SYRINGE_PUMP_HW_TOLERANCE_ML                  1.0F                                  ///< HW volume variance of the syringe pump in mL. TBD value.
+#define SYRINGE_PUMP_FILL_VOLUME_OFFSET_ML            0.8F                                  ///< Advised fill volume offset due to HW variance.
 
 /// Enumeration of syringe pump operations.
 typedef enum SyringePumpOperations
Index: firmware/App/Modes/ModeTreatmentParams.c
===================================================================
diff -u -rfed8ef4f0540818dfb7ca670a65eac39c12cb25a -r0e457429d65039d16cd631c3aaa06b5409de67c4
--- firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision fed8ef4f0540818dfb7ca670a65eac39c12cb25a)
+++ firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision 0e457429d65039d16cd631c3aaa06b5409de67c4)
@@ -560,7 +560,7 @@
                                 stagedParams[ TREATMENT_PARAM_VEN_PRESSURE_LOW_LIMIT ].sInt;
     F32 heparinVolume_mL = ( stagedParams[ TREATMENT_PARAM_HEPARIN_DISPENSE_RATE ].sFlt * \
                            ( stagedParams[ TREATMENT_PARAM_TREATMENT_DURATION ].uInt - stagedParams[ TREATMENT_PARAM_HEPARIN_PRE_STOP_TIME ].uInt ) ) + \
-                             stagedParams[ TREATMENT_PARAM_HEPARIN_BOLUS_VOLUME ].sFlt + SYRINGE_PUMP_PRIME_VOLUME_ML + SYRINGE_PUMP_HW_TOLERANCE_ML;
+                             stagedParams[ TREATMENT_PARAM_HEPARIN_BOLUS_VOLUME ].sFlt + SYRINGE_PUMP_PRIME_VOLUME_ML + SYRINGE_PUMP_FILL_VOLUME_OFFSET_ML;
 
 
     // Check max dialysate volume dependency