Many plants require a minimal level of KH (this is the CO2 level in your
water) to grow. If you want fast, beautiful growth, it is worth trying to
change. Unless you are injecting CO2, there isn't much point to changing pH,
GH, and you'll have no control over KH.

I think you misunderstand the relationship between KH, pH, and CO2.

KH is not the CO2 level in your tank. It's the amount of carbonate in the
tank, which isn't the same thing. And injecting CO2 does not give you control
over KH.

I do agree that plants need some KH. If your KH is zero, it's definitely worth
trying to increase it. But you don't do that with CO2. You do it with
carbonate. Baking soda, calcium carbonate, etc.


Leigh

http://www.fortunecity.com/lavender/halloween/881/