Zygo hybrid losing leaves

[Reeses]

I have a Zygo. Rhein Harlequin x Zygo. Advance Australia that is not doing very well. I repotted it 6 months ago in a mix from Repot Me for Paphs and Phrags, and its root system looked pretty good. However, it keeps losing leaves! They'll mature, but then start to turn yellow and die off. It is currently growing a new pb, but even the little baby leaves on the pb are turning brown.
I know Zygos tend to be cool-intermediate temperatures; day temps in my apartment tend to be 73-75, but night can drop down to 67. Maybe it's too warm for it?

I haven't seen any other signs of disease, and none of my other plants are having any problems. However, my others are all phals, paphs, catts, and oncs, so mostly warm growers.
Any ideas?

[fishmom]

That does seem warm for a zygo, although I though the Advance Australia hybrids were less demanding about temperatures than some others. Can you put it near an open window at night to get a better cool-down? 67 is pretty warm for a minimum temperature.

[Dollythehun]

Mine has about the same temps. But, I have a small fan blowing over them. Do you let it get dry? Because they love moisture. I am having a similar problem with my Tst. "Blue Fairy," which is in standing water.

[Reeses]

Yeah, my guess it is probably is not staying wet enough. I try to water at least once a week, and I keep my plants on a humidity tray with an added humidifier in the winter months, but that's probably not enough. Keeping the window open is a good idea, but I don't see it being feasible all the time. I am starting to wonder if I might need to re-home this guy