diff --git a/autotest/pst_from_tests.py b/autotest/pst_from_tests.py
index c2d59adc..2922db1b 100644
--- a/autotest/pst_from_tests.py
+++ b/autotest/pst_from_tests.py
@@ -974,6 +974,15 @@ def test_mf6_freyberg(tmp_path):
     #                   upper_bound=10, lower_bound=0.1)
 
     # add SP1 spatially constant, but temporally correlated wel flux pars
+    kper = 5
+    list_file = "freyberg6.wel_stress_period_data_{0}.txt".format(kper)
+    pf.add_parameters(filenames=list_file, par_type="grid",
+                      par_name_base="twel_mlt_{0}".format(kper),
+                      pargp="twel_mlt_{0}".format(kper), index_cols=[0, 1, 2],
+                      use_cols=[3], upper_bound=1.5, lower_bound=0.5,
+                      geostruct=gr_gs,
+                      mfile_sep=r'\s+')
+
     kper = 0
     list_file = "freyberg6.wel_stress_period_data_{0}.txt".format(kper+1)
     pf.add_parameters(filenames=list_file, par_type="constant",
diff --git a/pyemu/utils/pst_from.py b/pyemu/utils/pst_from.py
index d67cf20b..a033af4d 100644
--- a/pyemu/utils/pst_from.py
+++ b/pyemu/utils/pst_from.py
@@ -1048,6 +1048,8 @@ def _par_prep(
                         sep = " "
                         if rel_filepath.suffix.lower() == ".csv":
                             sep = ","
+                    elif sep == '\s+':
+                        sep = " " # sep for saving
                 if pd.api.types.is_integer_dtype(df.columns):  # df.columns.is_integer(): # really!???
                     hheader = False
                 else: