Is CO₂ necessary for aquarium plants?

CO₂ supplementation benefits aquarium plants in various ways. A low-light species like Java Moss does not require added CO₂ to promote good growth; instead, maximum growth is achieved using natural dissolved carbon. A highlight plant, such as a carpeting species, grows densely at concentrations of around 25-30 ppm. Match your CO₂ usage to your light intensity to prevent algae problems.

Avoid oxygen depletion. Turn off the CO2 injection when the lights are out, as the plants are respiring and will use up oxygen. Use air stones at this time to ensure enough surface movement for gaseous exchange between the water and air. These procedures are necessary to avoid stressing the fish, but enable the plants to grow during the day.

Identify signs of CO₂ depletion in plants: slow growth and small foliage are often indicators of not having enough carbon, and pale, new growth coupled with these signs point to too much or insufficient light. When you notice these signs, slowly and gradually change your injection rates and you will have healthier plants.

Combine CO₂ with proper fertilization. Plants have a more complete ability to utilize nutrients when adequate carbon is involved. Apply liquid fertilizers to CO₂ systems before each morning, when the system is initiated. Nitrate levels should remain relatively stable between 5 and 10 ppm for efficient nutrient uptake without promoting unwanted algae growth.

CO₂ success is signified by vigorous plant growth. When you see pearl-like bubbles on the leaves, your plants are absorbing carbon at their maximum. Begin initial plantings in your aquarium with durable plants, and then gradually add systems for CO₂ as your experience grows. This will help develop the sustainable planted aquarium that you envision.

Read the full article: Essential Aquarium Plant Care Guide