diff --git a/app/celery/reporting_tasks.py b/app/celery/reporting_tasks.py
index 8231e0613..d88c62deb 100644
--- a/app/celery/reporting_tasks.py
+++ b/app/celery/reporting_tasks.py
@@ -67,14 +67,9 @@ def create_nightly_billing_for_day(process_day):
 @notify_celery.task(name="create-nightly-notification-status")
 @cronitor("create-nightly-notification-status")
 @statsd(namespace="tasks")
-def create_nightly_notification_status(day_start=None):
-    # day_start is a datetime.date() object. e.g.
-    # 4 days of data counting back from day_start is consolidated
-    if day_start is None:
-        day_start = convert_utc_to_bst(datetime.utcnow()).date() - timedelta(days=1)
-    else:
-        # When calling the task its a string in the format of "YYYY-MM-DD"
-        day_start = datetime.strptime(day_start, "%Y-%m-%d").date()
+def create_nightly_notification_status():
+    day_start = convert_utc_to_bst(datetime.utcnow()).date() - timedelta(days=1)
+
     for i in range(0, 4):
         process_day = day_start - timedelta(days=i)
         for notification_type in [SMS_TYPE, EMAIL_TYPE, LETTER_TYPE]:
diff --git a/tests/app/celery/test_reporting_tasks.py b/tests/app/celery/test_reporting_tasks.py
index e8d86d1a0..f6fb40a3b 100644
--- a/tests/app/celery/test_reporting_tasks.py
+++ b/tests/app/celery/test_reporting_tasks.py
@@ -50,16 +50,15 @@ def test_create_nightly_billing_triggers_tasks_for_days(notify_api, mocker, day_
 
 
 @freeze_time('2019-08-01')
-@pytest.mark.parametrize('day_start, expected_kwargs', [
-    (None, ['2019-07-31', '2019-07-30', '2019-07-29', '2019-07-28']),
-    ('2019-07-21', ['2019-07-21', '2019-07-20', '2019-07-19', '2019-07-18']),
-])
-def test_create_nightly_notification_status_triggers_tasks_for_days(notify_api, mocker, day_start, expected_kwargs):
+def test_create_nightly_notification_status_triggers_tasks_for_days(notify_api, mocker):
     mock_celery = mocker.patch('app.celery.reporting_tasks.create_nightly_notification_status_for_day')
-    create_nightly_notification_status(day_start)
+    create_nightly_notification_status()
 
     assert mock_celery.apply_async.call_count == 4 * 3  # four days, three notification types
-    for process_date, notification_type in itertools.product(expected_kwargs, ['sms', 'email', 'letter']):
+    for process_date, notification_type in itertools.product(
+        ['2019-07-31', '2019-07-30', '2019-07-29', '2019-07-28'],
+        ['sms', 'email', 'letter']
+    ):
         mock_celery.apply_async.assert_any_call(
             kwargs={'process_day': process_date, 'notification_type': notification_type},
             queue=QueueNames.REPORTING