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Do I need to add carbon dioxide (CO2) to my fish tank?

All plants need carbon dioxide. Carbon dioxide is used in photosynthesis - the process by which plants make their own food.

If you have normal lighting levels, a single fluorescent strip for example, you should not need to add carbon dioxide to your aquarium. However, if you do, you will be rewarded with lush plant growth (the type you see in the aquarium magazines).

If you are using high density lighting, then Carbon dioxide injection is essential as it prevents algal growth that can occur with bright lights.

There are two methods of introducing carbon dioxide into your tank:

1. Fermentation - carbon dioxide is produced during the fermentation process. Good yeast based kits are available for smaller tanks (under 100 litres or 29 gallons). The yeast mixture produces carbon dioxide and this is bubbled through your tank.

2 Pressurised carbon dioxide cylinders - if you have a larger aquarium, then you should consider a pressurised carbon dioxide system. However, these can be expensive.

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