Phalaenopsis with stringy roots

[dianecty]

Hi again! I bought this mini-phal from Trader Joe's. At the time there were only a few roots. They looked sparse but ok.

I repotted it and the next day the flower drooped.

The leaves started looking dehydrated and so I watered it a little bit. After a week, I submerged the roots in banana tea for 24 hours and then rinsed it.

In the following days, the rest of the flowers drooped, then the buds.

Today, I cut off the spike below the flowers, depotted it and discovered that the roots rotted! I removed the rot.

And I put it in an old PET bottle with a little water at the bottom with only one root touching the water. Is this ok? What remedy would you suggest to save this plant?

Thank you!