Cymbidiums rescue

[dimithar]

Hi guys! I'm in need of assistance again I got these Cymbs today from a friend who doesn't want to care for them any more. Three large plants and a baby, as you can see on the photos. Two of the large plants seem pretty healthy, the third is turning black (eek!) in places and I'm very worried about it. I haven't cared for Cymbidiums yet. So, should I re-pot them? I think I want to use a mix of ordinary potting soil and fine bark to get more air (I can't even tell what these *were* in). Sorry for the bad photos, but I wanted some help on the blackening ASAP. What should I do with that one?