[cdavis]

Hi azapa,

A good question and hard to answer, too individual. Skywalkers point is well taken, very easy to overdo it. A large number of divers overbreathe without knowing it.

Here's my experiance, maybe its a helpful example, but don't assume it is the same for you.

I can't just relax and breath "normally", overbreath every time. I've gone to a breathing pattern that insures a relatively high co2 level. After the initial recovery breaths, 1 second inhale, slow exhale until feeling the urge to breathe(for me, this works up to 20-25 seconds), 2-3 times dive time, followed by 20 seconds or less of relaxed, mostly diaphramic purge breaths and go. Total surface interval is in the range of 3-4 times down time in 20-35 m. After a while, I've learned to recognize a level of relaxation and readiness that makes for a long and comfortable dive. This system gets me to a consistant level of "high" co2, the short set of purges knock off the edge without blowing off too much co2. Note, purges on top of overbreathing are a bad idea. You have to be careful with them. Many divers object to purging, for good reason, but IMHO it depends how its done. Also probably is important to consider what type of hunt, aspeto vs chase. I'd be more careful with purges if doing aspeto. For your own info, I'd suggest researching the issue.

You may find that this pattern takes a little longer, but thats ok, it makes the surface less boring and longer is considerable safer.

On surface interval, I used to dive a pattern very similar to yours, surface interval slightly longer than down time. However, after diving with people who use very long surface intervals and watching their results, I've discovered that longer works better, at least for me.

Hope this helps a little.

Connor