diff --git a/tenant_schemas/postgresql_backend/base.py b/tenant_schemas/postgresql_backend/base.py
index d6ae824..8602051 100644
--- a/tenant_schemas/postgresql_backend/base.py
+++ b/tenant_schemas/postgresql_backend/base.py
@@ -185,14 +185,15 @@ class ContentTypeCacheDescriptor(object):
             # use weak for transient Manager
             owner._thread_local_cache._cache = weakref.WeakKeyDictionary()
         global_cache = owner._thread_local_cache._cache
-        get_cache = global_cache.get(owner)
+        model_cache = global_cache.setdefault(obj, weakref.WeakKeyDictionary())
+        get_cache = model_cache.get(obj.model)
         if not get_cache:
             # use an LRU cache to evict dead tenants with time and to prevent
             # bloat with lot of tenants
             @lru_cache(maxsize=200)
             def get_cache(schema_name):
                 return {}
-            global_cache[owner] = get_cache
+            global_cache[obj.model] = get_cache
         tenant = getattr(connection, 'tenant', None)
         schema_name = getattr(tenant, 'schema_name', 'public')
         return get_cache(schema_name)