Should I aerate or agitate my cultures with CO2 and/or air?

The decision to agitate cultures with air or CO₂ is strain dependent. Most algal strains benefit from gentle agitation and increased levels of CO₂ (up to 1.5%). However, some strains of algae are sensitive to agitation. Also, the addition of CO₂ can cause a drop in pH. Therefore, if cultures are supplemented with CO₂, the pH should be closely monitored.