Err..Mortis there is no "switching" and no instantaneous. Plants that can absorb and make use of Gluteraldehyde compounds execute chemical reactions with these compounds of which the end product is CO2. These CO2 molecules are identical to every other CO2 molecules that find their way into the plant tissues by gas injection. There is no difference so there is no internal gatekeeper checking to see where the CO2 came from. It simply appears from the series of internal reactions and is indistinguishable from any other CO2 molecule ever created in the galaxy.
Then, Rubisco proteins simply grab whatever nearby CO2 molecules are present, regardless of their origin, and transfer them to the reaction centers where the CO2 enters other reactions to be turned into sugar.
Therefore, by absorbing these liquid carbon products, the overall CO2 concentration within the plant increases in exactly the same way as if you were injecting more CO2 gas. Since the Gluteraldehyde is a liquid product, it's solubility is better than gas and it does not immediately try to come out of solution and escape the tank, like a rat out of a trap, as gasses tend to do.
So the benefit of Liquid Carbon is that it does not present the same kind of toxicity to fish via blood acidification and Oxygen deprivation that high levels CO2 do, but yet, at the end of the cycle the plant tissues become saturated with more CO2. As previously mentioned though it does present it's own form of toxicity. Gluteraldehyde is used in hospitals to clean and disinfect surgical instruments for example, so this is nothing to fool with. Do a search on the forum to learn more about Gluteraldehyde.
Plants cannot use any other form of Carbon except in the form of CO2. This is a really important concept to remember. So any product claiming to be an "alternative" source of Carbon for plants had better be somehow generating CO2 either externally or internally, otherwise the product is utter rubbish.
Hope this clarifies...
Cheers,
