[JohnJamesRambo]

I have my doubts about this. In my experience, a house full of cannabis plants photosynthesizing full tilt under 15,000 watts of lights would still show elevated CO2 when two people went to it and tended it. Maybe the algae get around that, but I need to see some numbers.

>A human breathes about 9.5 tonnes of air in a year, but oxygen only makes up about 23 per cent of that air, by mass, and we only extract a little over a third of the oxygen from each breath. That works out to a total of about 740kg of oxygen per year. Which is, very roughly, seven or eight trees' worth.

[pooper]

This is going off topic but what an interesting idea... Can plants work day and night if you give them light 24x7? I assume they don't need to rest or get tired?

[georgyo]

Plants do indeed have day night cycles, so they do need rest.

Just Google plant day night cycle.

[derrasterpunkt]

This depends, as far as I know, if the plant is doing C-3 or C-4 photosynthesis.