When CO2 goes into a solution of H20 (aqueous solution) it goes into an equilibrium that includes the Carbonate ion (CO3) and carbonic acid. Where this equilibrium falls in terms of proportions of each depends on atmospheric pressure, pH, other components of the solution, temperature, and oxygenation.
As a water chemist I can tell you there is no 'special' kind of CO2; as there is no 'special' kind of table salt- different salts look different like their shape or even color, but sodium chloride is the same molecule no matter what the salt shaker it's in looks like. You know what I'm getting at?
You want to add CO2 to a grow, you really need to be adding it to the atmosphere instead, and if you are just after the carbon, add a non-polar form (=simple sugars) to the res instead of something so unusual.