Hi, I am a keeper of various orchids, mainly Phaleonopsis, with a problem with one in particular, in that the newest leaves appear folded when they come out and dont grow much before they start to go black and leathery from the tip.

I had it out of the pot, and there were a couple of brown roots which I trimmed, and some healthy roots, and lots of silvery arial roots. It is also putting out 2 flower spikes at the same time as it has this leaf problem.

I noticed the compost looked black so I have bought some more and repotted.

does anybody have any idea what this black rot is, i can only find hints about over fertilization, but this plant is in the same compost as the others and I rarely use fertilizer and all the others flower for 6 months at a time. Thanks in advance!!