diff --git a/billard/admin.py b/billard/admin.py
index b6456d7..f3d142e 100644
--- a/billard/admin.py
+++ b/billard/admin.py
@@ -26,7 +26,7 @@ class DeskAdminForm(forms.ModelForm):
 
     def clean_desk_no(self):
         id = self.instance.id
-        client = self.instance.client
+        client = self.cleaned_data['client']
         desk_no = self.cleaned_data['desk_no']
         t = Desk.objects.filter(desk_no=desk_no, client=client).exclude(id=id)
         if t.count() > 0:
diff --git a/billard/migrations/0014_auto_20170211_2008.py b/billard/migrations/0014_auto_20170211_2008.py
new file mode 100644
index 0000000..e4d4d98
--- /dev/null
+++ b/billard/migrations/0014_auto_20170211_2008.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.5 on 2017-02-11 20:08
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billard', '0013_accounting'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='desk',
+            name='prize',
+            field=models.DecimalField(decimal_places=2, default=0.0, max_digits=5, verbose_name='Normelpreis'),
+        ),
+    ]
diff --git a/billard/models.py b/billard/models.py
index ae6d4ac..7b8c7fa 100644
--- a/billard/models.py
+++ b/billard/models.py
@@ -63,7 +63,7 @@ class Desk(models.Model):
     desk_no = models.IntegerField(verbose_name='Tischnummer')
     name = models.CharField(max_length=32, blank=True, null=True, verbose_name='Tischbezeichnung')
     enabled = models.BooleanField(verbose_name='Tisch aktiv')
-    prize = models.DecimalField(max_digits=5, decimal_places=2, blank=True, null=True, verbose_name="Normelpreis")
+    prize = models.DecimalField(max_digits=5, decimal_places=2, default=0.0, verbose_name="Normelpreis")
     prize_hh = models.DecimalField(max_digits=5, decimal_places=2, blank=True, null=True,
                                    verbose_name="Preis Happy Hour")