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?