Aquascaping Guide Part 2- CO2 Injection for Aquarium Plants UAE
- Claire
- Apr 16
- 3 min read
Carbon, in the form of CO₂ (carbon dioxide), is one of the main building blocks for plant growth. In nature, land plants easily absorb CO₂ from the air and through their roots because it is widely available in the atmosphere.
However, for underwater plants, CO₂ is much more limited. In natural water bodies, only small amounts of CO₂ (around 5–8 ppm) are available, coming from fish respiration, bacteria, and natural gas exchange.
This is why aquatic plants often grow towards the surface—not just for more light, but also to access CO₂ from the air.
In a planted aquarium, injecting CO₂ removes this limitation, allowing plants to grow faster, healthier, and more efficiently.
What is CO₂ Injection?
CO₂ injection is the process of adding carbon dioxide into your aquarium water to support plant photosynthesis.
Plants need three key elements:
Light
Nutrients
Carbon (CO₂)
Without enough CO₂, plants cannot fully use light and nutrients, leading to poor growth and algae problems.
Why Aquarium Plants Need CO₂
In nature, land plants absorb CO₂ easily from the air. However, underwater plants have limited access to CO₂, usually only 5–8 ppm from fish respiration and natural processes.
👉 This is why aquatic plants grow toward the surface—to access more CO₂.
By injecting CO₂ into your aquarium, you remove this limitation and significantly improve plant growth.
Benefits of CO₂ Injection
✔ Faster and healthier plant growth✔ Stronger colors (especially red plants)✔ Better carpet plant development✔ Reduced algae problems✔ Professional aquascape results.
Liquid CO₂ – Does It Work?
Many products marketed as “liquid carbon” are not true CO₂.
They contain glutaraldehyde
Provide very small amounts of carbon
Not enough for plant growth
However, they can help control algae like black beard algae (BBA).
CO₂ Equipment Explained
1 | CO₂ Tank | Stores gas (different sizes available). |
2 | CO₂ Regulator | Controls CO₂ flow and pressure. |
3 | CO₂ Check Valve | Prevents water from flowing back |
4 | Bubble Counter | Shows CO₂ flow rate |
5 | CO₂ Tubing | Prevents leaks and ensures durability |
6 | CO₂ Diffuser | Types include:
|
7 | Drop Checker | Shows CO₂ levels visually:
|
How to measure the right amount of CO2 for my tank and timing ?
Once your CO₂ system is set up, you need to adjust it to reach about 30 ppm of CO₂ in the water before your lights turn on. This ensures plants can start photosynthesis immediately.
You can estimate this by checking the pH. A drop of 1.0 pH usually means you have reached the correct CO₂ level. For example, if your pH starts at 7.8 and drops to 6.8 after adding CO₂, you are at the right level.
Steps to follow:
Measure your pH in the morning with lights and CO₂ turned off
Start CO₂ at about 2–3 bubbles per second, or until you see a steady stream of fine bubbles
Let it run for 1 hour, then test the pH again
If the pH has dropped by 1 point, your CO₂ level is correct
If not, increase CO₂ or run it longer and test again
Once you know how long it takes to reach the correct level, set your timer so CO₂ starts before your lights turn on.
Example:
If it takes 1.5 hours to reach target CO₂
Turn CO₂ ON 1.5 hours before lights
Plants use the most CO₂ in the first 2–3 hours of light, so timing is important.
Keep in mind:
High KH levels can slow down pH changes
If bubbles rise quickly to the surface, CO₂ is not dissolving properly
This may mean your diffuser is too small or the flow is too strong
The goal is stable CO₂ levels and good diffusion for healthy plant growth.
In Part 3 of the Aquascaping Guide we will discuss about the Nutrients.
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