Mystery Ailment on Phal Mini Mark?

[jje10001]

I got this rather sickly Phal Mini Mark a few months ago as a rescue, and from the start, the crown looked rather sickly & damaged, some of the leaves had some strange chlorotic tips, and the mother plant had thrown out a basal growth. The plant was around 1 year old.

On the other hand, the roots were extremely healthy, so I immediately repotted it out of its gross-looking moss into a moss-bark mixture, and trimmed off the chlorotic leaf tips (sealing with cinnamon). The orchid was placed in an environment where it got bright indirect light + a constant temperature of around 20-22C/70F.

At time of acquirement:




Month 1

Over the next month, the small leaves on the crown started to wither and become limp, and some strange pitting started to occur on the leaves.

I then removed the smaller leaves and then dusted the crown with cinnamon.




Month 2

It seems like the issues with the mother plant are not stopping- in this month, the next topmost leaf is starting to yellow and shrivel. The rest of the leaves remain green and firm, and root system seems to remain healthy (I removed the top layers of substrate to inspect).

Furthermore, the leaf on the basal growth is continuing to grow, though it seems to have stopped working on its roots for the time being.




At this point, I am considering some options:

I don't have any systematic fungicides, but I do have Physan20. No pests have been seen on this plant. There is no smell, and the pits remain firm, so I'm not sure if it's bacterial.

Do Nothing.) Keep as-is, and continue to monitor. I expect the mother plant to continue declining, but I will continue to topically treat any new issues with hydrogen peroxide and cinnamon.

1.) Remove the top & inspect for, and remove any potential rot. The best case scenario would be that this stops the decline, retaining at least two healthy lower leaves to help the basal growth continue its growth.

2.) Completely remove the top of the mother plant while retaining the roots, treating the basal growth as the main plant.

I know that I shouldn't expect any further growth on the mother plant, but my concern is that its ailment (if contagious), may spread to the basal growth. Any opinions as to what this problem might be, and what my course of action should be?