diff --git a/strax/processing/general.py b/strax/processing/general.py
index 483c8cbf6..d46ebe267 100644
--- a/strax/processing/general.py
+++ b/strax/processing/general.py
@@ -39,7 +39,7 @@ def sort_by_time(x):
     return x
 
 @numba.jit(nopython=True, nogil=True, cache=True)
-def _sort_by_time_and_channel(x, channel, max_channel_plus_one):
+def _sort_by_time_and_channel(x, channel, max_channel_plus_one, sort_kind='mergesort'):
     """
     Assumes you have no more than 10k channels, and records don't span
     more than 11 days.
@@ -49,7 +49,7 @@ def _sort_by_time_and_channel(x, channel, max_channel_plus_one):
     # I couldn't get fast argsort on multiple keys to work in numba
     # So, let's make a single key...
     sort_key = (x['time'] - x['time'].min()) * max_channel_plus_one + channel
-    sort_i = np.argsort(sort_key)
+    sort_i = np.argsort(sort_key, kind=sort_kind)
     return x[sort_i]
 
 
diff --git a/strax/processing/statistics.py b/strax/processing/statistics.py
index 3ed848094..98b37c2bd 100644
--- a/strax/processing/statistics.py
+++ b/strax/processing/statistics.py
@@ -40,7 +40,7 @@ def highest_density_region(data, fractions_desired, only_upper_part=False, _buff
                          'with a total probability of less-equal 0.')
 
     # Need an index which sorted by amplitude
-    max_to_min = np.argsort(data)[::-1]
+    max_to_min = np.argsort(data, kind='mergesort')[::-1]
 
     lowest_sample_seen = np.inf
     for j in range(1, len(data)):
diff --git a/strax/run_selection.py b/strax/run_selection.py
index 7982c1dd8..9d0b30f4e 100644
--- a/strax/run_selection.py
+++ b/strax/run_selection.py
@@ -306,7 +306,7 @@ def define_run(self: strax.Context,
     if isinstance(data, (pd.DataFrame, np.ndarray)):
         if isinstance(data, np.ndarray):
             data = pd.DataFrame.from_records(data)
-      
+
         # strax.endtime does not work with DataFrames due to numba
         if 'endtime' in data.columns:
             end = data['endtime']
diff --git a/strax/utils.py b/strax/utils.py
index 912061ce0..20f86a88a 100644
--- a/strax/utils.py
+++ b/strax/utils.py
@@ -543,7 +543,7 @@ def multi_run(exec_function, run_ids, *args,
                 if throw_away_result:
                     continue
                 result = f.result()
- 
+
                 # Append the run id column
                 if add_run_id_field:
                     ids = np.array([_run_id] * len(result),