diff --git a/bridge_master.py b/bridge_master.py
index 40154bd..06417ff 100644
--- a/bridge_master.py
+++ b/bridge_master.py
@@ -556,7 +556,7 @@ def topoTrimmer():
     for _src in TOPO:
         _dstrem = []
         for _dst in TOPO[_src]:
-            if TOPO[_src][_dst]['time'] - + _now > 1800:
+            if _now - TOPO[_src][_dst]['time'] > 1800:
                 _dstrem.append(_dst)
         for _remove in _dstrem:
             TOPO[_src].pop(_remove)