Tube-fans are optimal for the use of ventilation and deaeration in hydroponical planting rooms. Tube-fans are easy to install und very quiet. Normally the noise is created in the air hose by the air resistance. The optimal control of the exhaust tube-fans can be done by using a fan speed controller. As soon as the by a digital MIN/MAX-Hygro-Thermometer entered temperature is transgressed, the exhausting tube-fans will turn on full throttle automatically until the temperature lowers to normal; - then the tube-fans will run dimmed again.