Phal. pulcherrima terrestrial?

[Chlorophile]

I have a Phal. pulcherrima that I recently purchased and it seems to be in a mixture of bark and moss. It is in desperate need of re-potting but I am confused by what I read. Some sources say it is a terrestrial plant and needs sandy soil. I was hoping to transition it to S/H but now am unsure as to what the best media for it would be.

[Paphluvr]

I purchased my pulcherrima about 30 yrs. ago when it was still classified as Doritus and it's never been in anything other than medium bark and perlite. I've divided it many times, given pieces away and still have numerous pots of it, the largest with six spikes, three of which have been in bloom for a year. I don't know where you got the info about sandy soil, but it obviously (from my perspective) doesn't need it.