diff --git a/Database/Persist/MongoDB.hs b/Database/Persist/MongoDB.hs
--- a/Database/Persist/MongoDB.hs
+++ b/Database/Persist/MongoDB.hs
@@ -159,10 +159,10 @@
   (map u (map (T.unpack . unDBName . snd) $ persistUniqueToFieldNames uniq))
   (map DB.val (persistUniqueToValues uniq))
 
-pairFromDocument :: PersistEntity val
+pairFromDocument :: (PersistEntity val, PersistEntityBackend val ~ DB.Action)
                  => EntityDef
                  -> [DB.Field]
-                 -> Either String (Entity DB.Action val)
+                 -> Either String (Entity val)
 pairFromDocument ent document = pairFromPersistValues document
   where
     pairFromPersistValues (x:xs) =
@@ -278,20 +278,22 @@
         query = DB.select (filtersToSelector filts) (u $ T.unpack $ unDBName $ entityDB t)
         t = entityDef $ dummyFromFilts filts
 
-    selectSource filts opts = C.Source $ do
-        cursor <- lift $ DB.find $ makeQuery filts opts
-        return $ C.PreparedSource
-            { C.sourcePull = lift $ do
-                mdoc <- DB.next cursor
-                case mdoc of
-                    Nothing -> return C.Closed
-                    Just doc ->
-                        case pairFromDocument t doc of
-                            Left s -> liftIO $ throwIO $ PersistMarshalError $ T.pack s
-                            Right row -> return $ C.Open row
-            , C.sourceClose = return ()
-            }
+    selectSource filts opts = C.Source
+        { C.sourcePull = do
+            cursor <- lift $ DB.find $ makeQuery filts opts
+            pull cursor
+        , C.sourceClose = return ()
+        }
       where
+        mkSrc cursor = C.Source (pull cursor) (return ())
+        pull cursor = lift $ do
+            mdoc <- DB.next cursor
+            case mdoc of
+                Nothing -> return C.Closed
+                Just doc ->
+                    case pairFromDocument t doc of
+                        Left s -> liftIO $ throwIO $ PersistMarshalError $ T.pack s
+                        Right row -> return $ C.Open (mkSrc cursor) row
         t = entityDef $ dummyFromFilts filts
 
     selectFirst filts opts = do
@@ -304,18 +306,20 @@
       where
         t = entityDef $ dummyFromFilts filts
 
-    selectKeys filts = C.Source $ do
-        cursor <- lift $ DB.find query
-        return $ C.PreparedSource
-            { C.sourcePull = lift $ do
-                mdoc <- DB.next cursor
-                case mdoc of
-                    Nothing -> return C.Closed
-                    Just [_ DB.:= DB.ObjId oid] -> return $ C.Open $ oidToKey oid
-                    Just y -> liftIO $ throwIO $ PersistMarshalError $ T.pack $ "Unexpected in selectKeys: " ++ show y
-            , C.sourceClose = return ()
-            }
+    selectKeys filts = C.Source
+        { C.sourcePull = do
+            cursor <- lift $ DB.find query
+            pull cursor
+        , C.sourceClose = return ()
+        }
       where
+        mkSrc cursor = C.Source (pull cursor) (return ())
+        pull cursor = lift $ do
+            mdoc <- DB.next cursor
+            case mdoc of
+                Nothing -> return C.Closed
+                Just [_ DB.:= DB.ObjId oid] -> return $ C.Open (mkSrc cursor) $ oidToKey oid
+                Just y -> liftIO $ throwIO $ PersistMarshalError $ T.pack $ "Unexpected in selectKeys: " ++ show y
         query = (DB.select (filtersToSelector filts) (u $ T.unpack $ unDBName $ entityDB t)) {
           DB.project = [u"_id" DB.=: (1 :: Int)]
         }
diff --git a/persistent-mongoDB.cabal b/persistent-mongoDB.cabal
--- a/persistent-mongoDB.cabal
+++ b/persistent-mongoDB.cabal
@@ -1,5 +1,5 @@
 name:            persistent-mongoDB
-version:         0.7.0
+version:         0.8.0
 license:         BSD3
 license-file:    LICENSE
 author:          Greg Weber <greg@gregweber.info>
@@ -14,12 +14,12 @@
 
 library
     build-depends:   base               >= 4 && < 5
-                   , persistent         >= 0.7     && < 0.8
+                   , persistent         >= 0.8     && < 0.9
                    , text               >= 0.8     && < 1
                    , transformers       >= 0.2.1   && < 0.3
                    , containers         >= 0.2     && < 0.5
                    , bytestring         >= 0.9     && < 0.10
-                   , conduit
+                   , conduit            >= 0.2
                    , mongoDB            >= 1.2     && < 1.3
                    , bson               >= 0.1.6
                    , network            >= 2.2.1.7 && < 3