diff --git a/redis/redis_test.go b/redis/redis_test.go
index <HASH>..<HASH> 100644
--- a/redis/redis_test.go
+++ b/redis/redis_test.go
@@ -35,7 +35,8 @@ func TestAdd(t *testing.T) {
 
 func TestThreadSafeAdd(t *testing.T) {
 	// Redis Add is not thread safe. If you run this, the test should fail because it never received
-	// ErrorFull.
+	// ErrorFull. It's not thread safe because we don't atomically check the state of the bucket and
+	// increment.
 	t.Skip()
 	flushDb()
 	leakybucket.ThreadSafeAddTest(getLocalStorage())(t)
redis: explain why not thread safe