yellow leaves on ang sequipedale

[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?