Index: firmware/App/Modes/ModeTreatment.c
===================================================================
diff -u -ra99ba4c383d65b09a1681d1b7f74be94b3359412 -r5454f27c656e54b9f70e9daa2c2ff1b4ae2d7437
--- firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision a99ba4c383d65b09a1681d1b7f74be94b3359412)
+++ firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision 5454f27c656e54b9f70e9daa2c2ff1b4ae2d7437)
@@ -1080,7 +1080,8 @@
         presMaxUFVolumeML = getTreatmentParameterF32( TREATMENT_PARAM_UF_VOLUME ) * (F32)ML_PER_LITER;
 
         // New UF rate is how much UF is left to be done / remaining treatment time
-        F32 newUFDiffML    = ( ( presMaxUFVolumeML - getTotalMeasuredUFVolumeInMl() ) < 0.0F ? 0.0F : ( presMaxUFVolumeML - getTotalMeasuredUFVolumeInMl() ) );
+        F32 measUFVolML    = getTotalMeasuredUFVolumeInMl();
+        F32 newUFDiffML    = ( ( presMaxUFVolumeML - measUFVolML  ) < 0.0F ? 0.0F : ( presMaxUFVolumeML - measUFVolML ) );
         F32 newTxTimeS     = (F32)treatmentTime * (F32)SEC_PER_MIN;
         F32 elapsedTxTimeS = (F32)treatmentTimeMS / (F32)MS_PER_SECOND;
         F32 timeDiffMin    = (newTxTimeS - elapsedTxTimeS) / (F32)SEC_PER_MIN;