Congrats Miguel !
I wonder how sensitive this species is to pH and soil moisture ?
It would be nice if it's easier to keep alive than koltzschiana, which has the cerrado curse.
Adam, actually I have both: Arenosa and klotzschiana and they grow slowly.
Arenosa is in the ground (in black soil, not the cerrado curse) since 2014, and don´t need special care.
But klotzschiana is my third try. The previous (one try in a pot and other in the ground) were unsuccessfull and the seedlings died. In this third try, she is in the ground (also in black soil, not the cerrado curse), with no special care, and is going well.
Looks like Arenosa is more easy indeed.
As a side note, is interesting to say that Arenosa has redish new leafs, without "hair". klotzschiana has new leafs in light green and hairy .