Index: firmware/App/Modes/ModeGenDialysate.c
===================================================================
diff -u -r590c4b129a1b8fced97b8f653fb58e97fdf64a28 -re5c384741feb64828c1f4c32ff6daca07b20f46e
--- firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision 590c4b129a1b8fced97b8f653fb58e97fdf64a28)
+++ firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision e5c384741feb64828c1f4c32ff6daca07b20f46e)
@@ -60,8 +60,9 @@
 #define DIALYSATE_TEMP_LOWER_SAFETY_LIMIT_C             33.0F                                       ///< Dialysate lower bound safety temperature limit in C.
 #define DIALYSATE_TEMP_CLEAR_TIMEOUT_MS                 ( 10 * MS_PER_SECOND )                      ///< Dialysate temperature clear persistence timeout.
 #define DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_PERCENT    5.0F                                        ///< Dialysate conductivity out of target tolerance percent.
-#define DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_TIMEOUT_MS ( 30 * MS_PER_SECOND )                      ///< Dialysate conductivity out of target timeout in milliseconds.
+#define DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_TIMEOUT_MS ( 10 * MS_PER_SECOND )                      ///< Dialysate conductivity out of target timeout in milliseconds.
 #define DIALYSATE_CONDUCTIVITY_CLEAR_TIMEOUT_MS         ( 10 * MS_PER_SECOND )                      ///< Dialysate conductivity clear persistence timeout.
+#define BICARBONATE_CARTRIDGE_LOW_LEVEL_FACTOR          1.25F                                       ///< Bicarb mix volume vs steady-state factor for cartridge low.
 #define ZERO_DIAL_FLOW_RATE                             0.0F                                        ///< Zero dialysate flow rate
 #define SPENT_CHAMBER_FILL_MAX_COUNT                    10                                          ///< Total number of spent chamber fill allowed.
 #define BICARB_CHAMBER_FILL_TIMEOUT                     ( 1 * MS_PER_SECOND )                       ///< Bicarb chamber fill timeout.
@@ -112,6 +113,7 @@
 static void updateDialysateToDialyzerFlowRate( void );
 static void checkDialysateTemperature( void );
 static void checkDialysateConductivity( void );
+static void checkBicarbonateCartridgeLevelLow( void );
 static void monitorChamberLevelStatus( void );
 static void publishGenDialysateModeData( void );
 static U32 getFreshDialPumpInitialRpm( void );
@@ -167,6 +169,7 @@
     initPersistentAlarm( ALARM_ID_DD_ACID_CONCENTRATE_CONDUCTIVITY_HIGH, DIALYSATE_CONDUCTIVITY_CLEAR_TIMEOUT_MS, DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_TIMEOUT_MS );
     initPersistentAlarm( ALARM_ID_DD_BICARBONATE_CONDUCTIVITY_LOW, DIALYSATE_CONDUCTIVITY_CLEAR_TIMEOUT_MS, DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_TIMEOUT_MS );
     initPersistentAlarm( ALARM_ID_DD_BICARBONATE_CONDUCTIVITY_HIGH, DIALYSATE_CONDUCTIVITY_CLEAR_TIMEOUT_MS, DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_TIMEOUT_MS );
+    initPersistentAlarm( ALARM_ID_DD_BICARBONATE_CARTRIDGE_LOW_LEVEL, DIALYSATE_CONDUCTIVITY_CLEAR_TIMEOUT_MS, DIALYSATE_CONDUCTIVITY_OUT_OF_TARGET_TIMEOUT_MS );
 }
 
 /*********************************************************************//**
@@ -517,6 +520,11 @@
     // Update any dynamic treatment parameter changes
     updateTreatmentSettings();
 
+    // Advance steady-state bicarb volume calibration (continues from PreGen)
+    serviceSteadyStateBicarbVolCal();
+
+    checkBicarbonateCartridgeLevelLow();
+
 #ifdef ENABLE_ALARM_2
     //Check dialysate temperature high/low alarms
     checkDialysateTemperature();
@@ -1300,6 +1308,46 @@
 
 /*********************************************************************//**
  * @brief
+ * The checkBicarbonateCartridgeLevelLow function checks bicarbonate mix
+ * volume against confirmed steady-state volume for cartridge low (alarm 243).
+ * Triggered when Bicarbonate Volume > Steady State Bicarbonate Volume + 25%
+ * for continuous 10 sec (±150 ms) while in Bypass or Delivery.
+ * @details \b Inputs: getBicarbMixVol, getSteadyStateBicarbVolume, genDialysateState
+ * @details \b Outputs: none
+ * @details \b Alarms: ALARM_ID_DD_BICARBONATE_CARTRIDGE_LOW_LEVEL when
+ * getBicarbMixVol() > getSteadyStateBicarbVolume() * 1.25F
+ * @return none
+ *************************************************************************/
+static void checkBicarbonateCartridgeLevelLow( void )
+{
+    F32 currentBicarbVol = getBicarbMixVol();
+    F32 steadyStateVol   = getSteadyStateBicarbVolume();
+    F32 threshold        = steadyStateVol * BICARBONATE_CARTRIDGE_LOW_LEVEL_FACTOR;
+    BOOL outOfRange      = FALSE;
+
+    if ( ( FALSE == isSteadyStateBicarbVolumeValid() ) ||
+         ( steadyStateVol <= 0.0F ) ||
+         ( ( DD_GEND_DIALYSATE_BYPASS_STATE != genDialysateState ) &&
+           ( DD_GEND_DIALYSATE_DELIVERY_STATE != genDialysateState ) ) )
+    {
+        checkPersistentAlarm( ALARM_ID_DD_BICARBONATE_CARTRIDGE_LOW_LEVEL, FALSE, currentBicarbVol, steadyStateVol );
+    }
+    else
+    {
+        outOfRange = ( currentBicarbVol > threshold ? TRUE : FALSE );
+
+        if ( TRUE == isAlarmActive( ALARM_ID_DD_BICARBONATE_CARTRIDGE_LOW_LEVEL ) )
+        {
+            // Clear when volume returns to at or below threshold
+            outOfRange = ( currentBicarbVol <= threshold ? FALSE : TRUE );
+        }
+
+        checkPersistentAlarm( ALARM_ID_DD_BICARBONATE_CARTRIDGE_LOW_LEVEL, outOfRange, currentBicarbVol, steadyStateVol );
+    }
+}
+
+/*********************************************************************//**
+ * @brief
  * The publishGenDialysateModeData function broadcasts the generate dialysate
  * mode data at defined interval.
  * @details \b Inputs: genDialysateDataPublicationTimerCounter