As far as the type of colonic, it's a closed system and I'm not sure how much water is used. By letting my body do most of the work my therapist discovered that to fill the colon and then turn the water off and let me hold the water as long as I can works better to stimulate peristalsis.
I'd say I'm well hydrated. I drink 6-8 glasses of water daily in addition to 5 glasses of other beverages. I avoid caffeine and sodas.
I also watch my diet and I usually have 2-3 bowel movements a day.