Index: leahi_dialin/common/msg_ids.py
===================================================================
diff -u -rfa37e7c7c1796532f07f39ba89da5465a4a8451c -r4d55f49b2e3282cc0d5730eb50b5df497c952069
--- leahi_dialin/common/msg_ids.py	(.../msg_ids.py)	(revision fa37e7c7c1796532f07f39ba89da5465a4a8451c)
+++ leahi_dialin/common/msg_ids.py	(.../msg_ids.py)	(revision 4d55f49b2e3282cc0d5730eb50b5df497c952069)
@@ -249,6 +249,9 @@
     MSG_ID_DD_PISTON_PUMP_DATA_PUBLISH_OVERRIDE_REQUEST = 0xAF00
     MSG_ID_DD_PISTON_PUMP_START_STOP_OVERRIDE_REQUEST = 0xAF01
     MSG_ID_DD_PISTON_PUMP_FILL_AFTER_DISPENSE_OVERRIDE_REQUEST = 0xAF02
+    # Placeholder message
+    MSG_ID_DD_ALARM_STATE_OVERRIDE_REQUEST = 0xAF03
+    MSG_ID_DD_STOP_GEN_DIALYSATE_MODE_OVERRIDE_REQUEST = 0xAF04
 
     MSG_ID_FP_TESTER_LOGIN_REQUEST = 0xB000
     MSG_ID_FP_SOFTWARE_RESET_REQUEST = 0xB001
Index: leahi_dialin/dd/dialysate_delivery.py
===================================================================
diff -u -r77740bc2ccace473a471515cadd4bc1353360cd6 -r4d55f49b2e3282cc0d5730eb50b5df497c952069
--- leahi_dialin/dd/dialysate_delivery.py	(.../dialysate_delivery.py)	(revision 77740bc2ccace473a471515cadd4bc1353360cd6)
+++ leahi_dialin/dd/dialysate_delivery.py	(.../dialysate_delivery.py)	(revision 4d55f49b2e3282cc0d5730eb50b5df497c952069)
@@ -28,6 +28,7 @@
 from .modules.post_gen_dialysate import DDPostGenDialysate
 from .modules.pressure_sensors import DDPressureSensors
 from .modules.pre_gen_dialysate import DDPreGenDialysate
+from .modules.spent_chamber_fill import DDSpentChamberFill
 from .modules.temperature_sensors import DDTemperatureSensors
 from .modules.ultrafiltration import DDUltrafiltration
 from .modules.valves import DDValves
@@ -121,6 +122,7 @@
         self.post_gen_dialysate = DDPostGenDialysate(self.can_interface, self.logger)
         self.pressure_sensors = DDPressureSensors(self.can_interface, self.logger)
         self.pre_gen_dialysate = DDPreGenDialysate(self.can_interface, self.logger)
+        self.spent_chamber_fill = DDSpentChamberFill(self.can_interface, self.logger)
         self.temperature_sensors = DDTemperatureSensors(self.can_interface, self.logger)
         self.ultrafiltration = DDUltrafiltration(self.can_interface, self.logger)
         self.valves = DDValves(self.can_interface, self.logger)