All of the following is used in preventing Legionella infection, EXCEPT:

The prevention of legionellosis involves minimizing production of aerosols in public places from water that may be contaminated with Legionella. Prevention is complicated by the fact that, compared with other environmental bacteria, Legionella bacteria are relatively resistant to chlorine and heat. The bacteria have been isolated from hot water tanks held at over 50degC. Methods for decontaminating water systems are still under evaluation. Some outbreaks have been aboed by hyperchlorination, by correcting malfunctions in water systems, or by temporarily elevating the system temperature above 70degC. The installation of silver and copper ionization systems similar to those used in large swimming pools has been effective as a last reso in hospitals plagued with recurrent nosocomial legionellosis. Ref: Ray C.G., Ryan K.J. (2010). Chapter 34. Legionella. In C.G. Ray, K.J. Ryan (Eds), Sherris Medical Microbiology, 5e.