Index: firmware/App/Controllers/DialOutFlow.c
===================================================================
diff -u -r74be223d47ea7bb0ac7d814e74d3627d830a5fac -r358e32a9fb25a6929fc5bbd7ee1d8ed2c4b69920
--- firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 74be223d47ea7bb0ac7d814e74d3627d830a5fac)
+++ firmware/App/Controllers/DialOutFlow.c	(.../DialOutFlow.c)	(revision 358e32a9fb25a6929fc5bbd7ee1d8ed2c4b69920)
@@ -150,6 +150,10 @@
 static OVERRIDE_F32_T dialOutPumpMCCurrentmA = { 0.0, 0.0, 0.0, 0 };                        ///< Measured dialysate outlet pump motor controller current.
 static OVERRIDE_F32_T dialOutPumpRotorSpeedRPM = { 0.0, 0.0, 0.0, 0 };                      ///< Measured dialysate outlet pump rotor speed.
 static OVERRIDE_F32_T dialOutPumpSpeedRPM = { 0.0, 0.0, 0.0, 0 };                           ///< Measured dialysate outlet pump motor speed.
+#if 1 // TODO - remove test code
+static F32 ufMeasuredRate = 0.0;
+static F32 prevMeasuredVolumes[2] = { 0.0, 0.0 };
+#endif
 
 static U32 dopControlTimerCounter = 0;                                                      ///< Timer counter to determine when to control dialysate outlet pump.
 static U32 dopCurrErrorDurationCtr = 0;                                                     ///< Timer counter for motor current error persistence.
@@ -597,6 +601,12 @@
             F32 totVol = getTotalMeasuredUFVolumeInMl();
             F32 offsetPWMDutyCyclePct;
 
+#if 1 // TODO - remove test code
+            ufMeasuredRate = ( totVol - prevMeasuredVolumes[1] ) * 6.0;  // calculate UF rate based on change in volume over last 10 seconds
+            prevMeasuredVolumes[1] = prevMeasuredVolumes[0];             // update last 2 volumes for next time
+            prevMeasuredVolumes[0] = totVol;
+#endif
+
             // Get new PWM offset from PI controller
             offsetPWMDutyCyclePct = runPIController( PI_CONTROLLER_ID_ULTRAFILTRATION, refVol, totVol );
             // Add PWM offset to DPi PWM mirror for our new DPo PWM
@@ -702,7 +712,11 @@
         dialOutBroadCastVariables.refUFVolMl = getTotalTargetDialOutUFVolumeInMl();
         dialOutBroadCastVariables.measUFVolMl = getTotalMeasuredUFVolumeInMl();
         dialOutBroadCastVariables.measRotSpdRPM = getMeasuredDialOutPumpRotorSpeed();
+#if 1   // TODO - remove test code
+        dialOutBroadCastVariables.measSpdRPM = ufMeasuredRate;
+#else
         dialOutBroadCastVariables.measSpdRPM = getMeasuredDialOutPumpSpeed();
+#endif
         dialOutBroadCastVariables.measMCSpdRPM = getMeasuredDialOutPumpMCSpeed();
         dialOutBroadCastVariables.measMCCurrmA = getMeasuredDialOutPumpMCCurrent();
         dialOutBroadCastVariables.setPWMpct = dialOutPumpPWMDutyCyclePctSet * FRACTION_TO_PERCENT_FACTOR;