diff --git a/combo/apps/maps/migrations/0003_auto_20170603_1653.py b/combo/apps/maps/migrations/0003_auto_20170603_1653.py
index ddd2fbf3..3ae455ed 100644
--- a/combo/apps/maps/migrations/0003_auto_20170603_1653.py
+++ b/combo/apps/maps/migrations/0003_auto_20170603_1653.py
@@ -14,7 +14,7 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name='maplayer',
             name='cache_duration',
-            field=models.PositiveIntegerField(default=60, verbose_name='Cache duration'),
+            field=models.PositiveIntegerField(default=60, help_text='In seconds.', verbose_name='Cache duration'),
         ),
         migrations.AddField(
             model_name='maplayer',
diff --git a/combo/apps/maps/models.py b/combo/apps/maps/models.py
index 022f2827..5f2b1b32 100644
--- a/combo/apps/maps/models.py
+++ b/combo/apps/maps/models.py
@@ -125,7 +125,7 @@ class MapLayer(models.Model):
     icon = models.CharField(_('Marker icon'), max_length=32, blank=True, null=True,
                             choices=ICONS)
     icon_colour = models.CharField(_('Icon colour'), max_length=7, default='#000000')
-    cache_duration = models.PositiveIntegerField(_('Cache duration'), default=60)
+    cache_duration = models.PositiveIntegerField(_('Cache duration'), default=60, help_text=_('In seconds.'))
     include_user_identifier = models.BooleanField(
             _('Include user identifier in request'),
             default=True)
diff --git a/combo/data/migrations/0021_jsoncell.py b/combo/data/migrations/0021_jsoncell.py
index bbcceff1..e8987f8e 100644
--- a/combo/data/migrations/0021_jsoncell.py
+++ b/combo/data/migrations/0021_jsoncell.py
@@ -25,7 +25,7 @@ class Migration(migrations.Migration):
                 ('title', models.CharField(max_length=150, verbose_name='Title', blank=True)),
                 ('url', models.URLField(verbose_name='URL', blank=True)),
                 ('template_string', models.TextField(null=True, verbose_name='Display Template', blank=True, validators=[combo.data.models.django_template_validator])),
-                ('cache_duration', models.PositiveIntegerField(default=60, verbose_name='Cache duration')),
+                ('cache_duration', models.PositiveIntegerField(default=60, help_text='In seconds.', verbose_name='Cache duration')),
                 ('groups', models.ManyToManyField(to='auth.Group', verbose_name='Groups', blank=True)),
                 ('page', models.ForeignKey(to='data.Page', on_delete=models.CASCADE)),
             ],
diff --git a/combo/data/models.py b/combo/data/models.py
index a75d8ac5..b2703341 100644
--- a/combo/data/models.py
+++ b/combo/data/models.py
@@ -1775,7 +1775,7 @@ class JsonCell(JsonCellBase):
     template_string = models.TextField(_('Display Template'), blank=True, null=True,
             validators=[django_template_validator])
     cache_duration = models.PositiveIntegerField(
-            _('Cache duration'), default=60)
+            _('Cache duration'), default=60, help_text=_('In seconds.'))
     force_async = models.BooleanField(_('Force asynchronous mode'),
             default=JsonCellBase.force_async)
     varnames_str = models.CharField(_('Variable names'), max_length=200, blank=True,