So with 900 psi, since you knew where the boat was, you were confident of swimming underwater, a safety stop and a controlled ascent??The other thing I failed to mention about going into the blue water where you have no visibility back to the reef - watch your depth closely it is easy to dip low with no reference points.
Its always good to have an observant/helpful buddy, but at the end of the day, you are responsible for your own safety. I was on a dive on the BVI Aggressor - wreck of the willy t. I kept hearing this "sound" and could not figure out what it was. We got bored with the wreck, moved to a nearby reef - and I could still hear the sound.
When my wife got close, I could read her tank on my dive watch - and she had 1800 psi to my 900... We are normally within 200 psi. I was like crap that sound is my gear.... I took my BC off and my 1st stage had a huge leak. I knew exactly where the boat was and i gave her the cut throat sign and signaled 'follow me, we're done...' I hauled ass back to the boat, got a 2 min safety stop in and surfaced with around 200 psi.
It would have been avoided had she noticed my gear was malfunctioning, but it worked out and she'll be more cognizant next time.
What would you have done if you had 200psi when you looked and you were a ways from the boat? These are the scenarios I come up with!!