diff --git a/da/analysis/expand_molefractions.py b/da/analysis/expand_molefractions.py
index 2a5d9cb68a844dcf2ade29139e6a9311ebeeb8c1..29002a3ad16908d17b8034e956ba6f9e75582418 100755
--- a/da/analysis/expand_molefractions.py
+++ b/da/analysis/expand_molefractions.py
@@ -41,10 +41,9 @@ def write_mole_fractions(dacycle):
     """
 
     dirname = create_dirs(os.path.join(dacycle['dir.analysis'], 'data_molefractions'))
-#
-# Some help variables
-#
-    dectime0 = date2num(datetime(2000, 1, 1))
+    #
+    # Some help variables
+    #
     dt = dacycle['cyclelength']
     startdate = dacycle['time.start'] 
     enddate = dacycle['time.end'] 
@@ -78,7 +77,6 @@ def write_mole_fractions(dacycle):
         for ff in infiles1:
             infiles.append(ff.replace(d2,d1))
 
-    #infiles   = [join(s.compressed(),'') for s in infilename]
 
     ncf_in.close()
 
@@ -112,7 +110,6 @@ def write_mole_fractions(dacycle):
         filesitecode = ncf_fc_in.get_variable('sitecode')
 
         fc_sitecodes = netCDF4.chartostring(filesitecode).tolist()
-        #fc_sitecodes = [join(s.compressed(),'') for s in filesitecode]
 
         ncf_fc_in.close()
 
@@ -278,11 +275,8 @@ def write_mole_fractions(dacycle):
 
         for num in selected_obs_nums:
 
-            model_index = obs_num.tolist().index(num)
-            file_index = file_obs_nums.tolist().index(num)
-
-            #var = ncf_out.variables['modeldatamismatch']   # Take from optimizer.yyyymmdd.nc file instead
-            #var[file_index] = mdm[model_index]
+            model_index = np.where(obs_num == num)[0][0]
+            file_index = np.where(file_obs_nums == num)[0][0]
 
             var = ncf_out.variables['modelsamplesmean']
             var[file_index] = simulated[model_index, 0]
@@ -301,8 +295,8 @@ def write_mole_fractions(dacycle):
 
             for num in selected_fc_obs_nums:
 
-                model_index = fc_obs_num.tolist().index(num)
-                file_index = file_obs_nums.tolist().index(num)
+                model_index = np.where(fc_obs_num == num)[0][0]
+                file_index = np.where(file_obs_nums == num)[0][0]
 
                 var = ncf_out.variables['modeldatamismatch']
                 var[file_index] = np.sqrt(fc_r[model_index])