yellow leaves on ang sequipedale

[BillieG]

My ang sequipedale 's leaves are turning yellow. It is in the middle--not the lower leaves. I planted it in S/H and feed it weakly/weekly. I just changed to k-lite a few weeks ago. It looked healthy when I got it, but it was budding and the buds turned mushy and fell off. Then I repotted it in the S/H. This was around January or Feb, I think. It is in a bright window but not direct sun. Can anyone tell me what I should do?

[WhiteRabbit]

[DavidCampen]

I don'y use semi-hydro or k-lite but I do have an Angcm sequipedale that I got one and a half years ago. I see that cultivation information in Orchidwiz says to grow it in warm to hot conditions, 66 - 85 deg at night. I grow mine at a minimum temperature a bit above 60 deg. and minimum 60% humidity. It produced 2 flowers for me at the end of January.

The yellowing leaves certainly seem to indicate that the plant is in distress. Some photos might help. What do the roots look like?