diff --git a/seinflux.py b/seinflux.py
index 8e034e8..2f03360 100644
--- a/seinflux.py
+++ b/seinflux.py
@@ -322,8 +322,7 @@ class SEHistory(InfluxDBWrapper):
                 if flag:
                     devices[stream] = device
                 else:
-                    device = None
-                    devices.pop(device, None)
+                    devices.pop(stream, None)
                 devcombi = tuple(zip(*sorted(devices.items())))
                 if devcombi != combi:
                     if combi: