Index: firmware/App/Modes/StatePreTxRecirculate.c
===================================================================
diff -u -r2df4b8aede603cf05cd54a319d85b4fb60611487 -r4b9b19de74301d92a2bc42efff445330c48cf38d
--- firmware/App/Modes/StatePreTxRecirculate.c	(.../StatePreTxRecirculate.c)	(revision 2df4b8aede603cf05cd54a319d85b4fb60611487)
+++ firmware/App/Modes/StatePreTxRecirculate.c	(.../StatePreTxRecirculate.c)	(revision 4b9b19de74301d92a2bc42efff445330c48cf38d)
@@ -44,9 +44,9 @@
 /// Enumeration of Pre-Treatment Recirculation sub-states.
 typedef enum PreTxRecirculate_States
 {
-    PRE_TX_RECIRCULATE_STATE = 0,
-    PRE_TX_RECIRCULATE_STOPPED_STATE,
-    NUM_OF_PRE_TX_RECIRCULATE_STATES
+    PRE_TX_RECIRCULATE_STATE = 0,                              ///< Recirculation is active.
+    PRE_TX_RECIRCULATE_STOPPED_STATE,                          ///< Recirculation is stopped due to an alarm condition.
+    NUM_OF_PRE_TX_RECIRCULATE_STATES                           ///< Number of Pre-Treatment Recirculation sub-states.
 } PRE_TX_RECIRCULATE_STATE_T;
 
 // ********** private data **********