Please help -Oncidium root rot!

[Sahlabiya]

Thank you so much for this. I had been advised to water it two days after returning home from the nursery so I did it. I'm still learning about when it's necessary to let plants dry out. Anyway I bought an orchid pot (I had had it in a regular clay pot) and repotted it in medium bark + charcoal + clay hydroton beads. I went out of town for a month and instructed a friend to water it once a week. It looked nice and green when I picked it up (though no real new growth) but a closer inspection of its roots showed that some were still mushy with string cores. After taking those off and dusting with sulphur powder I've just put it into dry medium bark and will follow your guidelines - we'll see if this time it really mends....