when either the supply of peroxide or sodium hypochlorite is low as indicated by peroxide supply indicator 172 and sodium hypochlorite supply indicator 178 respectively detergent low light 56 is lit disinfectant low light 58 indicates that the supply of disinfectant is low as indicated by formalin supply indicator 144 when r o pump malfunction sensor 180 indicates that the r o pump p 17 is malfunctioning r o pump malfunction light 60 is lit when either peroxide pump malfunction sensor 168 or sodium hypochlorite pump malfunction sensor 174 indicates that the perioxide pump p 13 or sodium hypochlorite pump p 16 are malfunctioning detergent pump malfunction light 62 is lit disinfectant pump malfunction light 64 indicates that the formalin pump malfunction sensor 140 senses that the formalin pump p 15 is malfunctioning when air pressure pump malfunction sensor 130 indicates a malfunction in the pressure pump p 14 air pump malfunction light 66 is lit if any malfunction develops in the r o water producing machine the r o supply light 68 is lit it should be understood that although formalin is the preferred sterilizing medium any of the well known disinfectants for sterilizing such as glutaraldehyde are acceptable it should also be understood that other detergents other than sodium hypochlorite are acceptable the preferred detergent is a sodium hypochlorite sold and manufactured under the trademark clorox bleach by purex corporation similarly although hydrogen.