diff --git a/ampel-firmware/mqtt.cpp b/ampel-firmware/mqtt.cpp
index 2e71ae2417fefb24f52761072d9ba20fb3c2d423..b8abf6181ab45efaee142d7a82da67135f22d065 100644
--- a/ampel-firmware/mqtt.cpp
+++ b/ampel-firmware/mqtt.cpp
@@ -96,7 +96,9 @@ namespace mqtt {
       config::co2_calibration_level = messageString.toInt();
       Serial.print(config::co2_calibration_level);
       Serial.println(" ppm.");
-      sensor::startCalibrationProcess();
+      sensor::scd30.setForcedRecalibrationFactor(config::co2_calibration_level);
+      Serial.println(F(" Done!"));
+      Serial.println(F("Sensor 'calibrated' :D."));
     }
   }