Black Rot on Mini Catt Pseudobulb

[ViolinFin]

Just noticed this morning that a pseudobulb on my mini cattleya has some form of black rot form at the soil line and made it basically down to the rhizome.

I drenched it all in physan 20, cut the infected bulb completely off the rhizome and then some. Drenched in physan 20 again.
Now I have three tiny separate bulbs all with damaged roots. One doesnt even have roots anymore, so it is in container rehab until roots grow back. All are isolated from the rest of the orchids now.

I ordered phyton 27 because I may need a systemic fungicide to deal with it and saw that it is a good choice. Also sprayed the entire adjacent collection with physan 20.

How likely am I to recover this orchid now that it is all separated in to tiny, individual pseudobulbs?
Anything else I should do in the meantime to help the situation?
I am quite worried about the mini catts I had next to it.

[estación seca]

What are your growing temperatures? How are you watering?

[ViolinFin]

Growing temps are around 70-75F, between 35-50% humidity.
I kept the plants in the pots they were shipped in because they seemed well potted. And they are. But I missed something important about the way they were potted.

I assumed all the potting mixture was orchiata and perlite, but there are actually sphagnum balls under the root spread. I assume I have been overwatering at about 1-2 times a week when I thought the media was sufficiently dry. I water overhead most of the time in my sink, except recently to avoid washing off pesticides.

I do also think that the pseudobulb was slightly too far in to the media.
I have been spraying a lot of fluids on the foliage as well due to a small thrips outbreak. I cant imagine the added wetness from that would help...

[ViolinFin]

this is how my plant has been divided after the surgery. poor rootless fellow in the tupperware.

[estación seca]

If the cross is 50% or more Sophronitis coccinea the temperatures should be fine. Otherwise higher temperatures would help.

I wouldn't cut up a plant this small. The small pieces are unlikely to survive. Aeration at the roots is what's important; they can stay moist if temperatures are appropriate. Many Catts do better kept fairly dry when temperatures are cool.

Rots are usually the result of growing conditions being too far from ideal.

[ViolinFin]

I'm hoping to increase the latent Temps by adding some grow lights in to the shelf. It's only at 70F consistently because it's dark and cold outside at the moment

All the other mini catts I have seem to be growing well despite it, but I'm not sure that in itself is indicative of "good health"...

I hope I can push along the split psueudobulbs to survive with some rooting hormone once I know the rot hasn't spread to the whole plant. It has been a real great bloomer ever since I got it last year

[ViolinFin]

picture updates of growing conditions and "the infected":

It was finally sunny this midday and this is closer to what my temps usually would be on a proper day. Grow lights are arriving today so I can keep the temps and light up when the sun isnt around.

All you see on the bottom and mid tier are all mini and compact cattleyas. The infected was on the mid tier at the edge of the humidity tray. I sprayed the drip tray and all the plants with physan 20, should I spray more of the surrounding area again, or would that just be paranoia acting?

As for treating the infected guys, how long should it take for me to figure out if the rot is not present in the other plantlets anymore? I may be able to rehab them if I eradicate the rot

[estación seca]

I looked up Cattleya Nano Rubies. It's 50% Cattleya (Sophronitis) wittigiana, 25% Cattleya (Laelia) acuensis and 25% Cattleya (Laelia) milleri. It would probably prefer being quite moist during warm weather but quite dry during cool weather. I would suggest enclosing the two smaller pieces to get the humidity much higher.