Sera CO2-Start

The Sera CO2-Start is a simple, beginner-friendly CO2 fertilization system for planted freshwater aquariums up to about 120 liters (32 US gallons). Carbon dioxide is the most important nutrient for aquarium plants, and adding it promotes lush, healthy growth while gently shifting pH toward the slightly acidic range many plants and fish prefer. The set pairs a discreet CO2 diffusion reactor with sera CO2-Tabs plus, so you can start dosing CO2 without pressurized cylinders or complicated equipment. Part of our planted-tank aquarium plants range.

How It Works

• A CO2-Tab is placed in the in-tank diffusion reactor, where it releases carbon dioxide that dissolves into the water for your plants.
• No pressurized CO2 cylinder required, so it is easy to set up and run.
• Ideal for the popular smaller planted tanks up to 120 L / 32 US gal.
• Boosts plant growth and helps establish a stable, slightly acidic pH.

What Is Included

• sera CO2 diffusion reactor (mounts discreetly inside the aquarium)
• sera CO2-Tabs plus (the CO2-generating tablets)

Features

• Beginner-friendly, easy to install and operate with no previous experience needed.
• Discreet reactor that blends into the aquascape.
• Cylinder-free CO2, powered by refillable tablets.
• Made in Germany by Sera.

Specifications

Recommended Pairings

• Live aquarium plants to put the extra CO2 to work
• Plant fertilizers and additives for balanced nutrition
• sera CO2-Tabs plus refills to keep the system topped up

Frequently Asked Questions

Do I need a CO2 cylinder?
No. The CO2-Start uses tablets, so there is no pressurized cylinder to buy or refill.

What size tank is it for?
It is designed for smaller planted aquariums up to about 120 L / 32 US gallons.

Is this for freshwater or saltwater?
Freshwater planted aquariums.

How does CO2 help my plants?
Carbon dioxide is the key plant nutrient. Adding it supports stronger growth and helps maintain a stable, slightly acidic pH.