Incident Report

2025-07-26Thirds reached, diver was on the return leg (with 5 "T" junctions to navigate) when a stream of bubbles became evident, this was initially believed to be coming from the first stage but was traced to the 2nd stage (nearly new Poseidon Cyklon) the nut that connects the hose to the 2nd stage. Cylinder shut down, 2nd stage disconnected and reviewed, o ring appeared to be intact. Reconnected and a stream of bubbles was the result. Diver initially attempted to flutter the valve but this resulted in a very wet breath. Cylinder shut down again, 2nd stage was again disconnected and checked but fault could not be identified and could not be resolved when turned back on. Cylinder shut down again and diver made way back to entrance to commence decompression using alternate cylinder. Upon reaching the surface the equipment was checked in more detail and although the front part of the o-ring was intact, a small section of the reverse was gone.A real issue results in a spike of adrenalin and generates quite shaky hands and elevated breathing rate! In water - Allotting more time to review (more carefully) the 2nd stage properly from all angles would have resulted in quicker identification of the issue. Pre dive - A more comprehensive pre-dive check of equipment (upstream and downstream) may also have identified degradation of the o-ring. Don't take your equipment for granted!