Index: firmware/App/Monitors/Pressures.c
===================================================================
diff -u -r9554044bb0ef104eedf8034ac59e1322a52118c5 -r9110311d2fd86d929e0d78424718000d8bfa8cba
--- firmware/App/Monitors/Pressures.c	(.../Pressures.c)	(revision 9554044bb0ef104eedf8034ac59e1322a52118c5)
+++ firmware/App/Monitors/Pressures.c	(.../Pressures.c)	(revision 9110311d2fd86d929e0d78424718000d8bfa8cba)
@@ -51,7 +51,7 @@
 /// Pressure Limit minimum stabilization time before short stabilization time activation
 static const U32 PRES_LIMIT_MIN_STABILIZATION_TIME_IN_MS = ( PRES_LIMIT_STABILIZATION_TIME_MS - PRES_LIMIT_SHORT_STABILIZE_TIME_MS );
 
-#define PSI_TO_MMHG                         ( 51.715F )                                    ////< Conversion constant for PSI to mmHg
+#define PSI_TO_MMHG                         ( 51.715F )                                     ////< Conversion constant for PSI to mmHg
 
 #define VENOUS_PRESSURE_MIN_PSI             ( -30.0F )                                      ///< Minimum of scale for venous pressure sensor reading (in PSI).
 #define VENOUS_PRESSURE_MAX_PSI             ( 30.0F )                                       ///< Maximum of scale for venous pressure sensor reading (in PSI).
@@ -559,7 +559,7 @@
     filterBaroPressureReadings( fpgaBaroPresPSI );
 
     // Get latest dialysate pressure so we can calculate TMP
-    tmpPressure.data = ( getDialysatePressure() * PSI_TO_MMHG ) - getLongFilteredVenousPressure();
+    tmpPressure.data = getLongFilteredVenousPressure() - ( getDialysatePressure() * PSI_TO_MMHG );
 
     // Handle pressure limits state machine
     execPressureLimits();