a rebreather uses a caustic solution of chemicals to scrub the oxygen of carbon monoxide so it can be reused. scuba, typical scuba, you have a finite oxygen supply that's expelled as you breathe, that's why you get a stream of bubbles. a rebreather doesn't do that. plus, you can only go so deep with a rebreather (45 feet?). if the chemicals get ANY water in it, you will be breathing lime and other burning chemicals instead of o2...not the ingredients for a fun day! hahahahaha
