A conditioning system for reducing an oxygen content of water carried in a subsystem of an industrial plant includes an electrolysis unit having a hydrogen side, an anode, and a cathode. The anode and cathode are connected to the subsystem to decompose water into hydrogen and oxygen. A hydrogen/oxygen recombination catalyst is connected to the subsystem. The hydrogen/oxygen recombination catalyst follows the anode and cathode on the hydrogen side. A method for lag reducing an oxygen content of water carried in a subsystem of an industrial plant, includes the steps of electrolytically decomposing water from a subsystem of an industrial plant into hydrogen and oxygen, and using the hydrogen generated at the same time for recombining the oxygen contained in the water.