I came across many people growing Chlorella or Spirulina types of microalgae, inside bottles or canisters and that that they also bubbled CO2 into these containers artificially.
This question is basically comprised of two questions that will clarify what I am trying to understand:
- Why do they use bottles or any type of bottle-like canister?
- Why do they insert CO2 to the bottle artificially in cases the bottle doesn't have a cork ? If the claim is that enough CO2 won't be able to get through the bottle neck than why growing the algae inside a bottle\aquarium in the first place, and not in a tub with full exposure to the air?