Cymbidium with brown/yellow leaves

[bzotter]

Hi all,

I got this cymbidium about a year ago. It has slowly lost a few leaves at a time (would turn yellow then fall off) from older bulbs. But over the last few months, this has increased dramatically and now I have lost over half of the overall bulbs. There is some brown discoloration of the leaf tips, and also some brown plaque near the leaf bases and deep in the leaf crease. It also seems to affect the new growth coming up with brown plaques. The bulbs are not super squishy. There are no visible organisms under a magnifying glass. I water once per week, and it is maintained in my apartment (mid 70s day, mid 60s night, indirect light near a window next to a humidifier). I am not sure if this is some sort of root or crown rot, or a fungal infection? I have doused it in physan 2 or 3 times over the last 2 months, but it has had no effect. I would appreciate any advice!

Thanks in advance.
Brendan