diff --git a/labsw/__init__.py b/labsw/__init__.py
index d2a6d5c..0da2406 100644
--- a/labsw/__init__.py
+++ b/labsw/__init__.py
@@ -1 +1 @@
-__version__ = '0.1.6.1'
+__version__ = '0.1.6.2'
diff --git a/labsw/io.py b/labsw/io.py
index a58155f..1267094 100644
--- a/labsw/io.py
+++ b/labsw/io.py
@@ -41,8 +41,8 @@ def process_data_RH_logger(filepath, every):
 
     # Derivative
     delta = np.mean(df['time'].diff())
-    df['dMdt_SG'] = savgol_filter(df['dm_m'], window_length=10000, polyorder=1, deriv=1, delta=delta)
-    df['dMdt_diff'] = df['dm_m'].diff(periods=1000) / df['time'].diff(periods=1000)
+    df['dMdt_SG'] = savgol_filter(df['m_mf'], window_length=10000, polyorder=1, deriv=1, delta=delta)
+    df['dMdt_diff'] = df['m_mf'].diff(periods=1000) / df['time'].diff(periods=1000)
 
     h5path = os.path.splitext(filepath)[0]
     h5path += '-processed.h5'