What a beast! That phal is huge and healthy as a horse. Great advice above about repotting - the only thing I'll add is make sure you pre-soak the new bark mix before repotting - I try and pre-soak for at least 24 hours, rinsing out the bark mix every so often with new water to clear away the dust and debris.
Is this guy still in bloom? If so, please post pics of the flowers.