diff --git a/lib/localiser/localisation/sensor/server.ex b/lib/localiser/localisation/sensor/server.ex
index 23436fe..9ac8d8e 100644
--- a/lib/localiser/localisation/sensor/server.ex
+++ b/lib/localiser/localisation/sensor/server.ex
@@ -231,7 +231,7 @@ defmodule Localiser.Localisation.Sensor.Server do
       end
 
       stage = %{distance: distance, mean_rssi: mean_rssi, readings: classified}
-      new_completed = [stage | completed]
+      new_completed = [stage | Enum.reject(completed, &(&1.distance == distance))]
 
       broadcast_calibration(state.sensor_id, {:stage_complete, state.sensor_id, distance, classified, mean_rssi})