[SantaMonica]

Wow no answers. Well here...

The main pathway that higher alk may help algal growth is when rapid algal growth is limited by carbonates in the water. Algae first uses dissolved CO2 in the water to get carbon, and if growing fast this will become limiting quickly. So the algae switches to alk. Fast growing algae can reduce alk by up to 2 points a day, although usually less than 1 a day, so keeping the alk up will prevent this from being a limiting factor.