💨 CO₂ fertilization in the aquarium – when it makes sense and how to use it correctly
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🌿 Why CO₂ is so important
CO₂ (carbon dioxide) is, alongside light and nutrients, one of the most important factors for healthy plant growth in an aquarium. 🌱
Plants need CO₂ for photosynthesis to produce energy and oxygen. Without enough carbon, they grow slowly, become stunted, or even die – and algae take over. 😬
Many aquarium owners underestimate how much a targeted CO₂ supply improves plant growth, water quality and biological balance.
🧪 When CO₂ fertilization makes sense
Not every aquarium necessarily needs CO₂. Whether a CO₂ system is worthwhile depends on various factors:
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🌿 Heavily planted aquariums: CO₂ is almost always mandatory here.
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🍀 Aquascapes: Without CO₂, there is no dense growth or carpet plants.
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☀️ Strong lighting: The more light, the more CO₂ plants need.
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💧 Fast-growing plants: They consume a lot of CO₂ and only grow optimally with additional support.
💡 Rule of thumb: The more plants, light and fertilizer are used, the more important CO₂ is.
🌱 Benefits of CO₂ fertilization
✅ Improved plant growth: Denser, stronger and healthier.
✅ Fewer algae: Plants successfully compete with algae for nutrients.
✅ Stable water parameters: CO₂ can slightly lower and stabilize the pH value.
✅ More oxygen: Healthy plants produce more O₂ for animals and bacteria.
✅ Better colors: Plants show more intense colors and stronger leaves.
🪴 This is how CO₂ fertilization works in an aquarium
CO₂ fertilization essentially consists of three components:
1. 💨 CO₂ source
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Pressurized gas cylinder: constant supply, ideal for medium and large pools
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Bio-CO₂: an affordable solution for small aquariums, produced at home with sugar and yeast
2. 🌿 CO₂ diffuser
It atomizes the CO₂ into fine bubbles so that it dissolves in the water. The finer the bubbles, the better the absorption.
3. 📊 Bubble counter & check valve
This allows you to precisely control the CO₂ supply and prevent backflow of water.
👉 Tip: For best results, the CO₂ should be introduced evenly and constantly.
📊 What is the optimal amount of CO₂?
The ideal CO₂ level is around 20–30 mg/l .
Too little = poor growth 🌱
Too much = stress for fish 🐠
💡 A continuous testing solution shows you at any time whether the CO₂ level is correct:
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🟡 Yellow = too much
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🟢 Green = perfect
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🔵 Blue = too little
👉 You can find suitable CO₂ long-term tests and accessories in our shop.
🌿 Tips for successful CO₂ fertilization
☀️ 1. Coordinate light and CO₂ levels
The stronger the lighting, the more CO₂ plants need. Without CO₂, they cannot optimally utilize the light.
🍀 2. Supplement nutrients
CO₂ alone is not enough – plants also need nitrate, phosphate, potassium, and trace elements. Therefore, use liquid fertilizer or root fertilizer in addition.
⏱️ 3. CO₂ only during the lighting period
Plants only need CO₂ when exposed to light. Turn off the supply at night to save gas and avoid overdosing.
🪸 4. Combine CO₂ with invertebrates
Shrimp and snails indirectly benefit from healthy plants that produce more oxygen and maintain a stable biological balance.
👉 In our shop you will find suitable care products, fertilizers and invertebrates that optimally complement your CO₂ supply.
🧠 Common mistakes in CO₂ fertilization
❌ Too much CO₂: can stress or suffocate fish and shrimp.
❌ Irregular intake: disrupts growth and balance.
❌ Lack of control: without a continuous test, you don't know how much CO₂ is actually in the water.
❌ Light and nutrients not adapted: Plants cannot optimally utilize CO₂.
✅ Conclusion: CO₂ is the growth turbo for plants
CO₂ fertilization is key to dense plant growth, less algae, and stable water parameters. It's especially essential for planted tanks and aquascapes. 💨🌿
With the right dosage, control and care, you can create a healthy, stable and impressive underwater ecosystem.
👉 Discover plant fertilizers, test kits and invertebrates in our shop that perfectly complement your CO₂ supply.