For awhile my air plants have been going brown at the tips, so I tried soaking them for longer. However, now one is getting brown spots on the leaves and it looks like the side of some of the leaves are deteriorating. Another one is becoming discolored (a black/purple color) on the side of some leaves. The bases of the leaves are not mushy, but one has a brown spot at the base of its leaf. I have no idea what is going on. Your advice is much appreciated!