diff --git a/atlas/tables.py b/atlas/tables.py
index 186e8fa8..1fa8aef9 100755
--- a/atlas/tables.py
+++ b/atlas/tables.py
@@ -162,8 +162,8 @@ class ConditionTable(tables.Table):
     selection = tables.CheckBoxColumn(accessor="pk", orderable=False)
 
     synonym = tables.ManyToManyColumn(verbose_name="Synonyms")
-    synonym2 = tables.Column()
-    s = tables.Column()
+    synonym2 = tables.Column(empty_values=())
+    s = tables.Column(empty_values=())
     parent = tables.ManyToManyColumn(verbose_name="Parents")
 
     class Meta: