A method for removing soluble ferrous iron from a galvanizing flux solution includes circulating the flux solution through a concentration loop and injecting ozone into the concentration loop, wherein the ozone mixes with the flux solution and reacts with soluble ferrous iron to form insoluble ferric iron in the loop. Flux solution that is substantially free of insoluble ferric iron may be removed from the concentration loop through a filter medium such as a cross-flow microfilter, thereby concentrating the ferric iron in the concentration loop. The ozone may be injected through an eductor that utilizes motive force from a circulation pump, thereby reducing energy consumption and providing rapid mixing and reaction of ozone and ferrous iron.