Is CO2 beneficial for low light planted tanks?

There is a common belief that only high light tanks require injected CO2, or conversely, that injected CO2 needs to be paired with high light. But what about CO2 for low light planted tanks?

Plants benefit tremendously from CO2 in both high and low light aquariums. This has been conclusively proven in controlled experiments where plant growth was plotted under various CO2/light combinations. Read more here.

The graph below shows that when CO2 levels are increased, plant mass increases even when light levels are held constant. Even in low-light aquariums, CO2 has a significant effect on improving growth rate and plant health.

In fact, low light + CO2 is one of the most stable combinations available to aquarists. For aquarists looking for slower but healthy growth, using slightly lower light and CO2 levels is a perfect combination. It is also much easier to control algae problems in a low light tank.

Hardscape heavy setups such as Iwagumis are best run with the combination of CO2 injection paired with low light levels. This combination will allow the plants to grow in smoothly without causing algae to spawn on the rocks and other hardscape.

The tank above is grown with only 50 umols of PAR in the carpet area. All aquarium carpet plants can thrive at this low light level as long as it is paired with CO2 injection.