Yep - very good point - you can easily see my bias here since our "plants" were suspended in water (an algae farm) so it was never a concern for us - but if you

Yep - very good point - you can easily see my bias here since our "plants" were suspended in water (an algae farm) so it was never a concern for us - but if you look at the basic photosynthetic formula you need as many molecules of water as you do of CO2.