its a medical grade disinfectant, that is glutaraldehyde, which many plants can use as a carbon source. It doubles as an algaecide because simple plant forms (algae, pelia, val's) die from it.
So for small tanks, it can be used for a complete substitute for co2, or even large tanks (ibenu's 200+ gallon). Carbon sources are needed because it takes Light, nutrients and carbon to get lush growth. Also your goal is to provide enough carbon and nutrients that light will be the limiting factor on plant growth.
the BBA thread thats stickied will explain more about its use to battle algae
