A floating installation is described that can, for example, be used for the farming of marine organisms, where the installation comprises a bag to establish a main water reservoir, where the walls are fastened to a floating collar with at least one inlet pipeline for the supply of fresh water and with at least one outlet pipeline for discharge of water and waste from the net cage. The installation can also be used for storing of water, purification of water and for the treatment of water. Also described is a method for treatment of water that is supplied to a cage in a cage installation.
