The orchid bark mix that I use contains charcoal and perlite and doesn't add any nutrients to the soil; I'm not sure how much it changes the soil PH. I began using it about a dozen or so years ago because I always had a heavy hand at watering and my plants were suffering greatly from the heavy, water logged soil. The older I get, the lazier I get and nowadays my container plants are lucky to get watered once a month but with the high humidity here they seem to survive. I won't say that they always thrive but they do seem to fare better on the drier side than being water logged. I have lots of container plants but I'm really not the greatest caretaker.
