We all know by now CO2 makes our plants grow like crazy, but how??? Carbon dioxide (CO2) is 100% essential in plant growth whether they be on land or under water.  CO2 is present in all of our aquariums whether you have a CO2 producing system in place or not, it is present no matter what due to water surface absorption from the air you and I breath. So here’s how it works, following the light reaction in a plants chloroplast, witch generated small amounts of ATP and the high energy electron carrier molecule NADPH, the Calvin cycle now takes place. Now, the Calvin cycle also know as a process called Carbon Fixation is where CO2 is vital and you will soon see why. Using the energy from ATP and NADPH the Calvin cycle also takes in molecules of CO2 from outside the cell, (AKA your aquarium water) and reduces them into G3P AKA a sugar precursor that eventually gets modified into a usable sugar for the cell. Now, read this a few times and it will start to make sense. The more CO2 your plants can take in, the more sugars they can make, thus the more they can grow.  The sugars that are produced as a result of the Calvin cycle then travel out of the chloroplast to the mitochondria of the cell where the sugar is used in conjunction with other important molecules through biochemical pathways to produce the bulk of the cells ATP which is the real reason for why the plant can grow so fast and efficiently.  So, when it’s all said and done, the more CO2 your plants have access to, the faster and more efficient they can grow! Hope this helps!    

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