The waste from my 1st ro is about 470,not sure on what effect it has on the 2nd ro,
at that reading it probably wont last as long ,but it is suposed to be the most efficent way,i can fill up a 640 ibc in a couple of hours, not sure on how it works with 2 feeds and 2 waste
i got my info from sureclean, if you phone them they give you more info, there really helpfull