diff --git a/aleksis/apps/chronos/model_extensions.py b/aleksis/apps/chronos/model_extensions.py
index afad135f17191cfc6a329c439572619729d61de1..1607bd241868ee6c9c147ab22a90e1ed4a03647e 100644
--- a/aleksis/apps/chronos/model_extensions.py
+++ b/aleksis/apps/chronos/model_extensions.py
@@ -5,7 +5,8 @@ from jsonstore import BooleanField
 
 from aleksis.core.models import Person, Group, Announcement
 
-from .models import Lesson, LessonPeriod, TimetableType
+from .managers import TimetableType
+from .models import Lesson, LessonPeriod
 
 
 @Person.property
diff --git a/aleksis/apps/chronos/util/build.py b/aleksis/apps/chronos/util/build.py
index b8d1fb261c8711e0d705d0f751a6be35d6c7e730..9fbc4ce5a629993983ca3adabc57c3d19f39864e 100644
--- a/aleksis/apps/chronos/util/build.py
+++ b/aleksis/apps/chronos/util/build.py
@@ -6,7 +6,7 @@ from calendarweek import CalendarWeek
 from django.apps import apps
 from django.db.models import QuerySet
 
-from aleksis.apps.chronos.models import TimetableType
+from aleksis.apps.chronos.managers import TimetableType
 from aleksis.core.models import Person
 
 LessonPeriod = apps.get_model("chronos", "LessonPeriod")
diff --git a/aleksis/apps/chronos/views.py b/aleksis/apps/chronos/views.py
index b0e593f57b59d172db0c1f4610fcec8867871414..3ddecc1526e257ed0e1196d0cef56e1b78790b71 100644
--- a/aleksis/apps/chronos/views.py
+++ b/aleksis/apps/chronos/views.py
@@ -15,7 +15,8 @@ from rules.contrib.views import permission_required
 from aleksis.core.models import Person, Group, Announcement
 from aleksis.core.util import messages
 from .forms import LessonSubstitutionForm
-from .models import LessonPeriod, LessonSubstitution, TimePeriod, Room, Holiday, Absence, TimetableType
+from .managers import TimetableType
+from .models import LessonPeriod, LessonSubstitution, TimePeriod, Room, Holiday, Absence
 from .tables import LessonsTable
 from .util.build import build_timetable, build_substitutions_list, build_weekdays
 from .util.js import date_unix