with respect to aluminum alloys in a desalination plant, it is essential to know what kind of environment they come into contact with and where they are used. In general the presence of chloride ions favors localized attacks and it is essential to prevent galvanic corrosion due to contacts (direct or indirect) with materials having a "nobler" potential (eg stainless steels, copper alloys, etc) often used in the mentioned plants. Among the indicated aluminum alloys, the 5xxx series have the highest resistance to an environment containing chloride ions and, for this reason they are the most widely used for marine applications.
Dear Dr. James William Jones, I'm very sorry for writing your name wrong .... unfortunately I tried to reply as quickly as possible and I made a mistake. Of course I confirm everything else !!!! Best regards. Pierluigi TRAVERSO