The sensor head of the GMP231 is heated during normal operation, which prevents condensation from forming inside the filter and on the optical surfaces. The heating is not on when GMP231 is in standby mode or unpowered. For this reason, keep the probe powered and operating when the incubator is in use and humidity inside the chamber is high.
Correct installation depth of the probe is also important for preventing condensation from running to the sensor along the chamber wall.