CO2 for Planted Tanks

There is nothing lovelier than a well-planted tank.

By David Lass | November 7, 2011

When folks start talking about keeping live plants in aquariums, the question always comes up of whether they “need” carbon dioxide (CO2) added to the tank.

Growing live plants in an aquarium is fairly popular these days, mostly, I think, because it is much easier to do. The lighting systems with high-output T5 fluorescent lamps and the newer LED lighting systems provide plenty of light for most live plants to thrive. There is nothing lovelier than a well-planted tank, as the fish and plants really do better with the other in the tank.

When folks start talking about keeping live plants in aquariums, the question always comes up of whether they “need” carbon dioxide (CO2) added to the tank. My answer is that it depends on what plants you want to grow; and it also depends on what you are going to have for lighting and for other supplemental feeding. It does no good to add CO2 to a planted tank unless you increase the intensity (not the duration) of the lighting, since the plants will require more light to process the extra food—carbon is the chief food for plants.

A number of different CO2 systems are currently available. There are a couple of simple yeast reactors, where yeast produces CO2 when it feeds on sugar—all in a little bottle with a hose that bubbles the CO2 into the tank. There are also pill-like additives that provide carbon for plants, which I have not used myself so I do not know how/if they work. I’ve also heard that you can use Alka Seltzer tablets, since the bubbles they release are CO2, but that seems to me to be expensive and rather hit or miss. There is a little machine from an Italian manufacturer of aquarium products that goes in the tank and produces CO2 in a different way. And, of course, there are the small—even tiny—CO2 cartridges with needle valves, which is the most reliable, but also the most expensive, way to provide CO2.

Whatever method your customer chooses (and I would suggest that you have a number of them offered for sale), they will be able to grow plants better and faster if they add CO2 to the tank. You should also get the additional sale of some stronger lighting, since with the added CO2 there must be additional light for the plants to use the CO2.