I do not think your melcourt mix is correct last time I spoke with Mike he told he had changed the mix to 1 part melcourt 1 part perlite 1 part small granite grit.
I used his first receipe (cannot remember the mix) which several sarracenia died and dionaea looked really rough, he said it was too heavy for the dionaea and I needed to pot them lightly.
I have done small trial and the sarracenia are growing fine. I have not tied dionaea in the revised version I have been told to try.
so David is this the mix you are using Mike has advised to use?