Index: firmware/App/Modes/ModeTreatment.c
===================================================================
diff -u -r04334ed8d1e927939718b1d62fb01afef0a2b9a9 -ra7104162b3467a67c5f4ed2f0f2ec038a8738d33
--- firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision 04334ed8d1e927939718b1d62fb01afef0a2b9a9)
+++ firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision a7104162b3467a67c5f4ed2f0f2ec038a8738d33)
@@ -34,6 +34,10 @@
 
 // ********** private definitions **********
 
+#define MAX_TREATMENT_TIME_MINUTES              ( 8 * MIN_PER_HOUR )
+#define MAX_UF_RATE_ML_MIN                      ( (F32)2500 / (F32)MIN_PER_HOUR )
+#define MAX_DIALYSATE_VOLUME_ML                 ( 180 * ML_PER_LITER )
+
 #define TREATMENT_TIME_DATA_PUB_INTERVAL        ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )  // interval (ms/task time) at which the treatment time data is published on the CAN bus
 
 /// Sub-mode states while in treatment mode
@@ -69,6 +73,10 @@
 
 static BUTTON_STATE_T lastOffButtonState = BUTTON_STATE_RELEASED;
 
+static U32 pendingUFVolumeChange;           ///< An ultrafiltration volume change (mL) is pending user confirmation.
+static F32 pendingUFRateChange;             ///< An ultrafiltration rate change (mL/min) is pending user confirmation.
+static U32 pendingTreatmentTimeChange;      ///< A treatment time change (min) is pending user confirmation.
+
 // ********** private function prototypes **********
 
 static TREATMENT_STATE_T handleTreatmentStartState( void );
@@ -336,6 +344,45 @@
 
 /*************************************************************************
  * @brief
+ * The verifyTreatmentDurationSettingChange function verifies the user treatment \n
+ * duration setting change.
+ * @details
+ * Inputs : none
+ * Outputs : none
+ * @param treatmentTime : Proposed new treatment duration (in min).
+ * @return TRUE if new treatment duration setting valid, FALSE if not.
+ *************************************************************************/
+BOOL verifyTreatmentDurationSettingChange( U32 treatmentTime )
+{
+    BOOL result = FALSE;
+    U32 timeDiff = 0;
+    F32 rateDiff = 0.0;
+    OP_MODE currMode = getCurrentOperationMode();
+
+    // check if we are in an appropriate treatment state for settings adjustment
+    if ( ( MODE_TREA == currMode ) && ( currentTreatmentState > TREATMENT_START_STATE ) && ( currentTreatmentState < TREATMENT_DIALYSIS_END_STATE ) )
+    {
+        U32 uFVolume;
+        U32 dialVolume = presDialysateFlowRate * treatmentTime;   // in mL
+
+        // always adjust UF volume to accommodate treatment time change (not UF rate)
+        uFVolume = (U32)( (F32)treatmentTime * presUFRate );
+        if ( ( treatmentTime <= MAX_TREATMENT_TIME_MINUTES ) && ( dialVolume <= MAX_DIALYSATE_VOLUME_ML ) )
+        {
+            result = TRUE;
+            pendingUFVolumeChange = uFVolume;               // mL
+            pendingUFRateChange = presUFRate;               // no UF rate change
+            pendingTreatmentTimeChange = treatmentTime;     // min
+            timeDiff = treatmentTime - ( (U32)( (F32)presTreatmentTimeSecs / (F32)SEC_PER_MIN ) + 1 );
+        }
+    }
+    sendChangeUFSettingsResponse( result, pendingUFVolumeChange, pendingTreatmentTimeChange, pendingUFRateChange, timeDiff, rateDiff );
+
+    return result;
+}
+
+/*************************************************************************
+ * @brief
  * The verifyUFSettingsChange function verifies new ultrafiltration settings \n
  * from the user.
  * @details
@@ -348,15 +395,55 @@
 BOOL verifyUFSettingsChange( F32 uFVolume, UF_ADJ_T adjustment )
 {
     BOOL result = FALSE;
+    U32 timeDiff = 0;
+    F32 rateDiff = 0.0;
     OP_MODE currMode = getCurrentOperationMode();
 
-    // check if we are in treatment mode
-    if ( MODE_TREA == currMode )
+    // check if we are in an appropriate treatment state for settings adjustment
+    if ( ( MODE_TREA == currMode ) && ( currentTreatmentState > TREATMENT_START_STATE ) && ( currentTreatmentState < TREATMENT_DIALYSIS_END_STATE ) )
     {
-        // check
-    }
-    //sendChangeUFSettingsResponse( BOOL accepted, U32 volume_mL, U32 time_min, F32 ufRate_mL_min, U32 timeDiff, F32 rateDiff );
+        // TODO - verify not too close to end of treatment for settings change
+        F32 uFRate;
+        U32 trtTime;
 
+        // reset pending UF/time settings change
+        pendingUFVolumeChange = 0;
+        pendingUFRateChange = 0.0;
+        pendingTreatmentTimeChange = 0;
+
+        // which setting does user want to adjust to accommodate the UF volume change? (treatment time or UF rate)
+        if ( UF_ADJ_TREATMENT_TIME == adjustment )
+        {
+            F32 uFRate = presUFRate;                            // no change in UF rate
+            U32 trtTime = ( uFVolume / uFRate ) + 1;            // in minutes
+            U32 dialVolume = presDialysateFlowRate * trtTime;   // in mL
+
+            // verify new treatment duration is valid
+            if ( ( trtTime <= MAX_TREATMENT_TIME_MINUTES ) && ( dialVolume <= MAX_DIALYSATE_VOLUME_ML ) )
+            {
+                result = TRUE;
+                pendingUFVolumeChange = uFVolume;
+                pendingUFRateChange = uFRate;
+                pendingTreatmentTimeChange = trtTime;
+                timeDiff = trtTime - ( (U32)( (F32)presTreatmentTimeSecs / (F32)SEC_PER_MIN ) + 1 );
+            }
+        }
+        else
+        {   // UF Rate is adjusted then
+            trtTime = presTreatmentTimeSecs / SEC_PER_MIN; // in minutes
+            uFRate = uFVolume / (F32)trtTime;
+            if ( uFRate <= (F32)MAX_UF_RATE_ML_MIN )
+            {
+                result = TRUE;
+                pendingUFVolumeChange = uFVolume;
+                pendingUFRateChange = uFRate;
+                pendingTreatmentTimeChange = trtTime;
+                rateDiff = ( uFRate - presUFRate );
+            }
+        }
+    } // current mode allows change
+    sendChangeUFSettingsResponse( result, pendingUFVolumeChange, pendingTreatmentTimeChange, pendingUFRateChange, timeDiff, rateDiff );
+
     return result;
 }
 
@@ -377,5 +464,16 @@
 {
     BOOL result = FALSE;
 
+    // user confirmed UF settings change(s)?
+    if ( TRUE == confirmed )
+    {
+        // user confirmed changes are same as verified pending changes?
+        if ( ( (S32)uFVolume == pendingUFVolumeChange ) && ( treatmentTime == pendingTreatmentTimeChange ) && ( ( uFRate - pendingUFRateChange ) < NEARLY_ZERO ) )
+        {
+            // TODO - implement changes, resume UF if appropriate
+            result = TRUE;
+        }
+    }
+
     return result;
 }