FIELD: water and air purification technology.SUBSTANCE: invention relates to preparation of water for cultivation of aquaculture. Method of purifying and preparing water in closed water supply systems for growing aquaculture involves a step of sampling 2 contaminated water from pool 1 or pools with aquaculture from any horizontal level of basin 1 or pools, step of primary mechanical treatment of collected water 3, carried out on filter with separation lamellas, stage of biological treatment of water 4, carried out on filter with bio-charging in pseudo-boiling layer at unidirectional movement from bottom to top of purified water and air, stage of secondary fine mechanical cleaning 5, carried out on filter with separation lamellas, stage of disinfection of water 7 by ozonation with simultaneous enrichment of water with oxygen at use of gas ozone-oxygen mixture under pressure of 1.05–1.40 bar with further maintenance of treated water at atmospheric pressure and control of final amount of ozone. At each purification step disposal of separated mechanical impurities 8 is provided. Water is circulated by pump 6. Cleaning equipment is connected in series in accordance with the sequence of said stages and placed on the process line to pump 6. Devices for ozonation, enrichment of water with oxygen and control of final amount of ozone are placed on pressure line of pump 6. Simultaneously, the equipment is installed so that the upper level of water in the mechanical filters and the upper level of the biofilter pseudo-boiling layer are made at the level of the pool or aquariums basins with vertical accuracy of -0.20 m and pump suction level at pool or aquarium pool level with vertical accuracy up to -0.50 m.EFFECT: invention reduces power consumption, increases degree of purification, efficiency of using oxygen and ozone-oxygen mixture, and improves operation reliability.5 cl, 1 dwgИзобретение относится к подготовке воды для выращивания аквакультуры. Способ очистки и подготовки