I found these studies very interesting please read them
This is about microalgae and phyto but may still relate
http://atarazanas.sci.uma.es/docs/tesisuma/16615220.pdf
Best read about bicarbonate use for macros its put in easy to understand language too.
use "bicarbonate" as a search term in the google search box on the left
http://books.google.com/books?id=zM8...ed=0CEQQ6AEwAg
Algae PH and carbon
http://reefkeeping.com/issues/2006-10/rhf/index.php
