being root bound with very little media in it is why they grow well. orchids don't need need much to hold em up. you can toss em on the kitchen counter and hose em down on occasion and they would grow. The media YOU need is the one thats going to fit YOUR conditions for the plant. The orchid doesnt need anything.
so when you ask what kind of mix does my plant need?. Ask yourselves also what kind of mix do I Need so my plant grows in the conditions I have?...
I tell you I hold mine up in chunky orchiata bark, dyna rok and charcoal. Nothing fancy. They do get lots of sun water and humidity most of the year in a toy greenhouse that give me lots of grief. Very little media as they tend to grow out of it anyway. They always seem to run from whatever you stick them in. The roots tend to grow in and on everything cept the mix