diff --git a/columbus/env.py b/columbus/env.py
index bfc2d77..ccd5259 100644
--- a/columbus/env.py
+++ b/columbus/env.py
@@ -111,7 +111,7 @@ class ColumbusEnv(gym.Env):
 
     def _seed(self, seed):
         if seed == None:
-            seed = self._master_rng()
+            seed = self._master_rng.random()
         self.rng.seed(seed)
 
     def random(self):