.
I am a Stanhopea man.
And I also cultivate but a dozen plants of the Genus Paphiopedilum.
Though I do not want to over-generalize here, I do generalize as follows.
(a) Plants with mottled leaves which, in nature, would grow in rainforest leaf litter, need acidic compost.
Example P. lawrenceanum.
(b) Plants with plain green leaves which, in nature, would grow in the cracks of weathered cristalline limestone rocks,
will not thrive in acidic compost. Example P. stonei.
Paphiopedilum aficionados, when potting their plants,
should have the basics of (a) and (b) in mind
.