Gh nutes exp

Hey guys I been out game for a while and thinking on starting a new batch pretty soon my nutes from general hydronic have been sitting for a while how long do they last? Do they expire? The micro looks fine you know is a dark blue color but the bloom is a orangey reddish color and notice some sort rust or residue on the bottle is that normal ?

they really don't expire. its all on how you store them. some will start to crystallize when there old or got to much o2 in it.. i have used gh nutes that was a few years old with no issues..