Eric while doing more research on this I came across an older post by you and I am a bit confused by it based upon what you have said in these posts, is this older post how you used to feel about alkaline and now after more research you feel differently? thanks
"Either way, alkalinity causes problems. First of all, the Hb-O2 affinity is modified. The more alkaline you are, the more your Bohr effect will be reduced in the end of apnea. This can cause a premature blackout, not unlike hyperventilating. A very alkaline person is more likely to black out during packing also (again because Hb-O2 affinity is too high and other reasons). In short, acidic blood is very helpful in the end of apnea. Your body expects to be acidic, so don't fool it.
Actually, Peter and I, after long experiments, came up with a simple rule before deep diving. We often do a pre-dive static on the surface--at this point we are not particularly relaxed, nor do we do a big breathe up, so we don't expect big times. During our pre-dive surface static, we should get contractions around 2:05 to 3:00. If we make significantly more than 3:00 with no contractions, we are too alkaline and we risk a premature blackout during the dive. Diving when too alkaline feels like diving after hyperventilating, and physiologically it is quite similar. The symptoms are simple: some light-headedness on the final breath/and/or during packing, feeling great during the whole dive until the last 20m, when suddenly you feel like crap, you get uncomfortable-style contractions, and things tend to start fading in a hurry. On one such a dive, I had a small samba after only 2 contractions during the dive."
