I can't figure out what I have been doing wrong with this plant. If you look below the name tag you can see part of the caudex that was below the soil is dried looking. I just cut the green vine off because it wilted and looked terrible. I took it out of the soil to photograph and noticed the dried part but below that is in good shape and the roots are nice and white and growing. Earlier in the spring I put the plant in S/H but it was not doing well there so in August I moved it back into soil and I may have lowered the caudex into the soil at that time. I wonder if that caused the problem.
Pterodiscus needs help
Could be, I don't know. Do you have a "before" picture of the plant?
When in doubt, repot to the same level the plant was originally growing at. If you do lift it, the process should be gradual.
If this was my plant, I would consider the top layer of pellets in the semi-hydro pot as top dressing, basically. That's the level to which your top dressing should probably go in the final container. Chunky pumice or something airy like that can be applied extra-thick as a sort of buffer on top, should you wish to experiment.
I don't know what to say about the caudex, but the roots look very healthy and the plant would probably benefit from being put back in soil before the fine tips all dry out.
I don't have any other pictures of it. I repotted it in S-H and lowered it in the medium. I think I raised it too much too fast. I had it "resting" in my potting mix to keep the roots covered and as soon as I read your response I went out and worked on it. I'll let you know how it goes and if it survives! But, darn, I love those great roots so I hope it will make it!