Why do rebreather divers make bubbles?
First, when any diver descends, the airspace in their mask is compressed and they must exhale through the nose to equalize the “mask squeeze”. Ergo, bubbles on descent, whether diving open circuit or CCR. Some have this down to a fine art that loses little excess gas during descent. Second, during the dive, sometimes a little seawater gets into the mask (as does mucus from the nasal passages). How much mask clearing depends on the fungus growth on the latex skirt of the diver’s mask, whether or not they ae clean shaven (unlikely on a weekend) and how clear the sinuses are during the dive. Also how many times the CCR diver’s open circuit buddy totally flubs it and the CCR diver is LMAO in reaction. Water (or snot) in the mask requires the standard mask clearing maneuver: lift the head up and exhale through the nose. Ergo, bubbles during the dive, as above. Third, on ascent, the gas in the CCR diver’s “breathing loop” expands naturally due to the decreasing ambient pressure. To remove th
