diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## 0.16.5
+### Removed
+- Remove concurrency from xpub balance requests to prevent RocksDB segfaults.
+
 ## 0.16.4
 ### Removed
 - Remove concurrency from requests using iterators to prevent RocksDB from segfaulting.
diff --git a/haskoin-store.cabal b/haskoin-store.cabal
--- a/haskoin-store.cabal
+++ b/haskoin-store.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 8ab386452576005ff6acda2b569d7e1219303832c0c0271c8a43b4c32e960acc
+-- hash: 545948e0c4f4a34a7d6185ca86f13515e6f723853f2722c630202699fa2bf266
 
 name:           haskoin-store
-version:        0.16.4
+version:        0.16.5
 synopsis:       Storage and index for Bitcoin and Bitcoin Cash
 description:    Store blocks, transactions, and balances for Bitcoin or Bitcoin Cash, and make that information via REST API.
 category:       Bitcoin, Finance, Network
diff --git a/src/Network/Haskoin/Store/Web.hs b/src/Network/Haskoin/Store/Web.hs
--- a/src/Network/Haskoin/Store/Web.hs
+++ b/src/Network/Haskoin/Store/Web.hs
@@ -820,59 +820,25 @@
 
 xpubBals ::
        (MonadResource m, MonadUnliftIO m, StoreRead m) => XPubKey -> m [XPubBal]
-xpubBals xpub = do
-    (rk, ss) <- allocate (newTVarIO []) (readTVarIO >=> mapM_ cancel)
-    stp0 <- newTVarIO False
-    stp1 <- newTVarIO False
-    q0 <- newTBQueueIO 20
-    q1 <- newTBQueueIO 20
-    xs <-
-        withAsync (go stp0 ss q0 0) $ \_ ->
-            withAsync (go stp1 ss q1 1) $ \_ ->
-                withAsync (red ss stp0 q0) $ \r0 ->
-                    withAsync (red ss stp1 q1) $ \r1 -> do
-                        xs0 <- wait r0
-                        xs1 <- wait r1
-                        return $ xs0 <> xs1
-    release rk
-    return xs
+xpubBals xpub = (<>) <$> go 0 <*> go 1
   where
-    stp e =
-        readTVarIO e >>= \s ->
-            if s
-                then return ()
-                else await >>= \case
-                         Nothing -> return ()
-                         Just x -> yield x >> stp e
-    go e ss q m =
+    go m =
         runConduit $
-        yieldMany (as m) .| stp e .| mapMC (uncurry (b ss)) .| conduitToQueue q
-    red ss e q = runConduit $ queueToConduit q .| f ss e 0 .| sinkList
-    b ss a p = mask_ $ do
-        s <-
-            async $
-            getBalance a >>= \case
-                Nothing -> return Nothing
-                Just b' -> return $ Just XPubBal {xPubBalPath = p, xPubBal = b'}
-        atomically $ modifyTVar ss (s :)
-        return s
-    as m = map (\(a, _, n') -> (a, [m, n'])) (deriveAddrs (pubSubKey xpub m) 0)
-    f ss e n
-        | n < 20 =
-            await >>= \case
-                Just a ->
-                    wait a >>= \case
-                        Nothing -> f ss e (n + 1)
-                        Just b -> yield b >> f ss e 0
-                Nothing -> return ()
-        | otherwise = do
-            atomically $ writeTVar e True
-            await >>= \case
-                Just a -> do
-                    cancel a
-                    atomically $ modifyTVar ss (Data.List.delete a)
-                    f ss e n
-                Nothing -> return ()
+        yieldMany (addrs m) .| mapMC (uncurry bal) .| gap 20 .| sinkList
+    bal a p =
+        getBalance a >>= \case
+            Nothing -> return Nothing
+            Just b' -> return $ Just XPubBal {xPubBalPath = p, xPubBal = b'}
+    addrs m =
+        map (\(a, _, n') -> (a, [m, n'])) (deriveAddrs (pubSubKey xpub m) 0)
+    gap n =
+        let r 0 = return ()
+            r i =
+                await >>= \case
+                    Just (Just b) -> yield b >> r n
+                    Just Nothing -> r (i - 1)
+                    Nothing -> return ()
+         in r n
 
 xpubUnspent ::
        ( MonadResource m