Stanhopea ruckeri w/ leaf troubles

[musicloveranthony]

I have a Stanhopea ruckeri that has some sort of infection of its leaves. The larger leaves have a rapidly advancing death of tissue, with brown/yellow/gray discoloration. Some of the pseudobulbs also seem to be darker than others.

As far as culture, they're in 65-70% humidity, low light, fan about 6 feet away, air around 65 degrees at night 70 degrees during the day. Sphagnum around the roots in a teak basket. Water every 3-4 days as the sphagnum dries

My Stanhopea grandiflora is starting to develop spots on the leaves...i'm really hoping they're not going to have to be sacrificed...