To provide long term safe storage of grain the proper aeration is essential. This is made by various aeration systems. In the flat bottom of the round cylindrical silobins a special floor system is installed made of perforated sheets. Blowing air into the silobin through these sheets the whole grain column can be aerated. Its advantage against to the traditional air duct system that at this special floor the whole grain surface of the round silobin can be aerated.