I know that we all have our own ideas, but I was just reading some stuff online and came across this from a very well respected source regarding Bicalcarata care:
Next, repot your plant in the standard mix of peat moss and perlite (1 part of each). We've found that this species grows best in a peat-based mix. Naturalists who have examined the natural habitat of the bicalcarata also confirms that this species grows in a peat type of soil.
Hmm. Any thoughts?