co2 questions

[nitrous]

when u get to 2 wpg why do u need co2 and i kno co2 helps the plants so why does this help the plants and what does it truely do and why do u need it at 2 wpg?

 

[Wizzard~Of~Ozz]

Mainly algae control. Carbon is a Macro nutrient (same as NO3, PO4 and K), without it you plant consume all available carbon then stop, the algae takes over because you have a deficiency.

Co2 is really needed with any lighting. at low light you can increase the growth by 3-4%, meaning even in low light, Carbon is the limiting factor. as you go up in light, the consumption get's higher and the difference becomes more evident.