Bulbophyllum A-Doribil Anna Roth leaf fading
 

I'm at a loss, after considerable research I can't seem to diagnose why the leaves on my Bulbophyllum A-Doribil Anna Roth are fading and loosing their leaves. The plant is grown under LED lights, daytime temperatures range in the mid to high 70's, good air flow and watered weekly using MSU fertilizer with additional calcium added to the mix and monthly flushes with epsom salt flush every other month. The only thing might be humidity, currently levels are low during the day ranging from 40% to 50% with night time levels ranging 50% to 65%. The humidity issue is currently being resolved so I can maintain 60% to 70%. Any help will greatly be appreciated.
Cheers, Bernie

I could be wrong, but it loos WAY too dry. Bulbo's should never dry out.

Thanks Ray.
I didn't think that I let it dry out, but certainly will monitor that a bit closer.

And maybe too much light. But keep wetter as well.

Thanks DeaC. I'm going to start out with keeping it a bit wetter as well as increasing the humidity to 70% now that I have my humidity system up and working.