CO2 bottles for freshwater aquarium

In a planted aquarium, _CO2 is the secret fuel for lush landscapes. By supplying this pressurized gas, we replicate the richness of natural rivers: plants absorb nutrients faster, intensify their pigments, and deprive algae of a habitat. The Zoanthus store has assembled a complete range of cylinders adapted to every size, from desktop nano-sized tanks to XXL tanks.

Why inject CO₂ into a planted aquarium?

Leaves submerged in water only have access to a small amount of atmospheric CO₂. A controlled supply increases photosynthesis , which results in:

• denser growth, ideal for Dutch hardscape or competing aquascaping tanks;
• more vivid colors, especially on the often capricious red plants;
• a slightly lowered pH which benefits species from South America or Asia;
• fewer filamentous algae, defeated by nutrient competition.

In short, a CO₂ bottle transforms an ordinary aquarium into a veritable underwater forest.

The different types of CO₂ cylinders for aquariums

Disposable bottles: practical and ready to use

Ultra simple: screw on, diffuse, recycle. The cartridge is pre-pressurized; no refills required. For supplemental tanks or beginner aquarists, it's a no-brainer. Small budget, great flexibility . The essentials:

• Dennerle disposable CO2 bottle
• JBL Aquarium disposable CO2 bottle
• Tetra disposable CO2 bottle
• Tropica disposable CO2 bottle

Refillable bottles: economical in the long term

A single purchase for years of service. The steel casing withstands dozens of refills, and each refill costs a fraction of the price of a new cartridge. They're ideal for CO₂-intensive bins or for everyday use. Their robustness, several months of battery life, and reduced environmental footprint are the hallmarks of their success.

• Aqua Nova refillable CO2 bottle
• JBL Aquarium rechargeable CO2 bottle

Bottles with integrated regulator

The factory-installed pressure regulator prevents leaks and screwing errors—perfect for beginners or those short on time. Pressure adjustment is achieved with a simple turn of a dial, without the need for additional tools.

CO₂ bottles for nano aquariums

Small volumes require light diffusion to avoid overdosing: mini bottles (50 to 95 g) deliver a very fine flow, ideal for cubes of 10 to 40 L. Their compact size can be easily hidden behind a root or in an office cabinet.

How to choose the right CO₂ bottle?

The right size depends on three criteria: tank size, plant density, and diffusion frequency. A heavily planted tank often uses 0.8 g of CO₂/L per month . Need help? Zoanthus offers a range of CO2 accessories (precise regulators, bubble counters, check valves) to fine-tune the dosage.

Use and maintenance of a CO₂ cylinder

Screw the regulator flat, test the seal with soapy water, then adjust the bubble counter. At night, it is essential to turn off the gas to avoid a free-falling pH: solenoid valve on the programmer or connection to a pH controller. When the pressure drops below 30 bars, schedule a recharge or exchange. Complete CO2 kits include everything needed for secure installation.