Stir Crazy, I haven't read Calfo's book, but everything I've read says that carbonate and calcium is created from CO2 reactor effluent at about the same proportion relative to one another as the consumption of the two during calcification of corals.
That being said, in my system I still have to add a little extra buffer to keep everything balanced. I assume its due to extra acids created by my fish and macroalgae.
Here's a link of most if not all of Randy Holmes-Farley's articles on Central Reef:
http://www.reefcentral.com/vbulletin...hreadid=102605