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