So what’s the difference between ‘The Closed System’ and ‘The Open System’ for Colon Hydrotherapy? ➡️ The Closed System involves the colon therapist inserting a speculum that contains tubes in the other end, which connects them to the colonic machine, and is generally about 1” in diameter. The client lays on their side as the therapist inserts this speculum approximately 4-5” into the rectum. The therapist then modulates the water pressure going into the client. After the session, the client goe