Diluent is injected into the breathing loop in one of two ways-either automatically through the
ADV/MAV, or manually by pressing directly on the ADV/MAV diaphragm.
The ADV is a demand valve and functions similarly to a standard 2″d stage. If the counterlungs fully collapse when the diver inhales, the negative pressure on the ADV diaphragm will cause the valve to open and add diluent. This allows the diver to take a full breath even if the counterlungs are “bottomed out.” This can be especially useful on descent where the loop volume is decreasing due to increasing water pressure.
Manually injecting diluent is also an option and may be used to perform a diluent flush. These skills will be covered in your class.
Servicing, Maintenance, & Cleaning
In order for the Optima CM to continue to perform properly, it must be cleaned and maintained regularly. Rebreathers require more maintenance and cleaning than standard open circuit SCUBA equipment. For their own safety, a rebreather diver should be committed to spending the time, effort, and money required to properly maintain the unit.