it is on SWRO plant with a capacity of 50000m3/day the tds of the feed is 41690ppm implying a chloride ion level of around 23000ppm the temperature of the feed is around 18C in March and 27C in September the reject has a tds of 64500ppm . the pressure is 70 bar, that plant started to produce water in June 2003 and corrosion problem appeared already few months of service, two type of corrosion could be established, one being crevice corrosion in 11/2" high pressure connector underneath victauling coupling example the same type of problem that have been corrosion in 316L and 317L high pressure piping seven out of 700 such connector were reported to have suffered this type crevice corrosion after 4 months only, provide the remedy to end the problem