I got narced the first dive to 100', which was a grotto dive, and, as Uncle Pug has said, was a "dark nark." On that dive, I was in very cold water with zero vis due to total darkness, and tanic water that would probably have no vis anyway. The symptoms from that dive were controllable anxiety, and moderate disorientation. I had a good instructor with me, and I called the dive and we ascended.
Now, my last dive to 100' was two days ago, again, with an excellent but differnent instructor (side note, the guy was wearing bp/wings with doubles, and I have to admit I have never seen a diver with the kind of buoyancy and trim control this guy had. It was almost hypnotic to see someone so still during a safety stop). The plan had been to do the dive in the Gulf, but bad weather forced another Grotto dive, this time to Blue Grotto in Willingston, Florida. Same depth, same dark conditions (this time due to overhead environment, not quality of water). This time, a TOTALLY different experience. Had a wonderfult dive. No anxiety, no disorientation with gauges.
Part of it may have been that this guy was such a professional, and we had spent so much time on our dive plan, that I had a feeling of control from the moment we descended. The only thing that may have represented some of the effects of nitrogen was that when we made our first safety stop, I was surprised the dive time was already 25 minutes. Seemed more like 15 minutes. However, time never "got away" from me, as I was riveted to my computer during the dive.
It'll be interesting to hear how your next deep dive goes, as one dive may not be at all representative of the next. Just make sure you have a highly competent buddy.
P.S.: One thing I forgot to mention is that first dive was compressed air, this was EANx34. If the texts are to be believed, shouldn't decrease the risk, but still noteworthy.
