diff --git a/ssa/alarm/lightstack.py b/ssa/alarm/lightstack.py
index 2c5b584..9a75f6d 100644
--- a/ssa/alarm/lightstack.py
+++ b/ssa/alarm/lightstack.py
@@ -92,7 +92,7 @@ class LightStack:
             thread.cancel()
             thread.join()
             self.channel_threads[channel] = None
-        self.off(channel)
+            self.off(channel)
 
     def get(self, channel):
         return self.channel_states.get(channel, None)