Need culture advice on C. jenmanii x C. percivaliana

[Tindomul]

Hi all,
Cattleya jenmanii 'Majestic ' x C. percivaliana 'Summit'
I have had this orchid for exactly a year now. It bloomed when I first got it, but in that entire year, has barely grown a single root. It put out a new leaf, but the top half is black, almost as if it had gotten burned. It get some strong sunlight in the early morning ours, filtered by windows and blinds at times, and in the last few months less light. So I doubt its sunburn.
I just don't know what Im doing wrong. I keep it potted in bark, carbon, and expanded clay pellets mix topped by some sphagnum. The sphagnum dries out every other day so I mist it every other morning. Is there a special temperature requirement for this orchid that I don't know about? Thanks.
I have also failed miserably at keeping C. jenmanii and even though I have three cuttings of C. percivaliana, none are really taking off. HELP!!!