The present invention relates to essential details of the design of an inflatable element (5), which can neither be moved nor deformed by the liquid (3), to its functional operation, and to the resulting predictable and repeatable ability to eliminate turbulent behavior and to influence the behavior of a liquid in a holder (2) or tank suitable for the storage or transport of liquids, in which the element at any liquid level and at any volume of liquid at least completely covers the horizontal liquid surface and in which the element can change both in size and in shape if required necessary by the geometry, the shape or the dimensions of the liquid holder or tank.