The above has happened on the small number of cave dives I have done with the CDG. I must admit I found the experience very unnerving as I felt at the time I was on the point of drowning. In my estimation the amount of water was too much to be breathed past or spat out. Fortunately I was near the start of the sump on both occasions and I was able to return to the surface regain some composure and complete the dive.
I was wondering whether the fact I was using a Poseidon Jetstream at the time could have been a contributory factor in the above incident? My local dive shop recommended that I should cover the holes on the outer circular rim of the second stage with tape and also try and align the whole thing facing downwards whilst diving. I don't know whether this is good advice? However, a member of the CDG with numerous years experience has tested the Jetstream and found no problems with water flooding suddenly into it.
I was wondering whether it is something I was doing wrong? I, however, used Apex regulators on my Open Water course and had no problems what so ever. Please note it has been recommended that I use Cyclon regultors which I have now purchased secondhand. After servicing last Feb. one set needs adjusting so might have to fall back on the Jetstream!