Psychopsis Mendenhall Help - Mites + Repotting

[vlhart]

Hey everyone!

I've got a psychopsis in need of help. Got it about three years ago and repotted it then in medium bark with a little sphagnum on top. It had about a year of good root growth and grew a new psedudobulb. Then things went down hill. The leaves have faded and lost the strong spotting they originally had. I realized some kind of small grayish mite was proliferating in the orchid (but found very few in neighboring orchids). They went away with increased humidity and regularly rinsing the plant.

This past year there has been some new root growth and one new pseudobulb, but the leaves have continued to fade and the pseudobulbs have wrinkled and do not firm up after watering. After a few weeks of not really paying much attention to it, I have just realized the mites are back (again, found very few in neighboring plants). It also has a new whitish coloring on one leaf tip (doesn't quite show in photo)--it's not cobwebby, just looks white and dusty but doesn't rub off. Also the potting medium is pretty broken down.

Looking for recommendations for next steps for this guy. Should I repot or not in the middle of winter? In a different medium? (I have med. lava rock, bark, coconut husk, sphagmum on hand). I know psychopsis are occasionally finicky. Does anyone recommend anything more for mites than regular rinsing and increased humidity? Also looking for general psychopsis care/potting tips as this one clearly isn't thriving. Thanks in advance for any wisdom you can impart!20181202_psychopsis320181202_psychopsis4 20181202_psychopsis2 20181202_psychopsis