diff --git a/xos/synchronizer/model_policies/model_policy_Image.py b/xos/synchronizer/model_policies/model_policy_Image.py
index 6d6982e..7e1a6f3 100644
--- a/xos/synchronizer/model_policies/model_policy_Image.py
+++ b/xos/synchronizer/model_policies/model_policy_Image.py
@@ -5,7 +5,7 @@
         # container images do not get instantiated
         return
 
-    controller_images = ControllerImages.objects.filter(image=image)
+    controller_images = ControllerImages.objects.filter(image_id=image.id)
     existing_controllers = [cs.controller for cs in controller_images] 
     
     all_controllers = Controller.objects.all() 
diff --git a/xos/synchronizer/model_policies/model_policy_Slice.py b/xos/synchronizer/model_policies/model_policy_Slice.py
index 953d2c9..68aa596 100644
--- a/xos/synchronizer/model_policies/model_policy_Slice.py
+++ b/xos/synchronizer/model_policies/model_policy_Slice.py
@@ -20,13 +20,14 @@
     # slice = Slice.get(slice_id)
 
     controller_slices = ControllerSlice.objects.filter(slice_id=slice.id)
-    existing_controllers = [cs.controller for cs in controller_slices] 
-        
+    existing_controllers = [cs.controller for cs in controller_slices]
+    existing_controllers_ids = [x.id for x in existing_controllers]
+
     print "MODEL POLICY: slice existing_controllers=", existing_controllers
 
     all_controllers = Controller.objects.all()
     for controller in all_controllers:
-        if controller not in existing_controllers:
+        if controller.id not in existing_controllers_ids:
             print "MODEL POLICY: slice adding controller", controller
             sd = ControllerSlice(slice=slice, controller=controller)
             sd.save()