Abstract: The present invention controls the concentrations of oxygen and carbonate gases in a hydroponic solution in a growing pool, by independently connecting online to a growing pool a hydroponic-solution feeder in the structure such that a plurality of semipermeable-membrane tubes to circulate liquid fertilizer (or water) is placed and arranged in a tank to circulate water (or liquid fertilizer), and a controller of dissolved gas concentration in the structure such that a hydroponic-solution conduit and a gas conduit are formed separately by arranging in the tank a separating membrane to pass only gas and prevent the permeation of liquid, and circulating oxygen and/or carbonate gas in the gas conduit of the controller of dissolved gas concentration, along with the circulation of the hydroponic solution in the growing pool through the hydroponic-solution conduit while appropriately controlling the concentration of liquid fertilizer in the hydroponic solution by means of the hydroponic-solution feeder, whereby the d