Fluval Bio-CO2 Pro System 250L
The ALL-NEW Fluval Bio-CO2 Pro system combines the safety of biological carbon dioxide production with the convenience of pressurized delivery. Offering simplicity and unparalleled performance in an easy to use format, Bio-CO2 delivers reliable and controllable CO2 through the naturally occurring fermentation process. With safe, low-pressure operation, it is the most secure, simple, and environmentally sustainable aquarium CO2 delivery system available.
- For tanks up to 66 gallons or 250 liters
- Includes: Nano bubble diffuser, 5 feet CO2 airline, stainless steel chamber, inline check valve, activator and booster solution, adjustable bubble counter
| Component | Description |
|---|---|
| Nano Bubble Diffuser | Creates fine bubbles for efficient CO2 dispersion |
| CO2 Airline | 5 feet length for flexible placement |
| Stainless Steel Chamber | Resists corrosion and ensures long-term durability |
| Inline Check Valve | Prevents backflow and maintains system integrity |
| Activator and Booster Solution | Starts and maintains fermentation process |
| Adjustable Bubble Counter | Allows precise control of CO2 output |
FAQ
What is the maximum tank size supported by the Fluval Bio-CO2 Pro System?
The system is designed for tanks up to 66 gallons or 250 liters.
Does the system require any external power source?
No, the system operates through a biological fermentation process and does not require electricity.
How does the adjustable bubble counter work?
The bubble counter allows users to adjust the rate of CO2 delivery by controlling the flow of bubbles, providing precise control over CO2 levels in the aquarium.

Peter Roberts –
Easy to set up and very reliable. The CO2 output is consistent and the bubble counter helps me maintain stable levels in my 55-gallon tank. No issues with leaks or bubbles escaping. Great for beginners and experienced aquarists alike.
Hannah Wallace –
I’ve tried several CO2 systems before, but this one is the most stable. The nano bubble diffuser works well and the fermentation process is quiet and safe. No maintenance needed beyond adding the booster solution.
Dylan Manning –
Works well for my 250-liter tank. The bubble counter is helpful, though it takes a few days to establish the fermentation process. Once running, it’s very consistent and doesn’t require any power.
Mary Hughes –
Love the simplicity. No electricity, no complicated setup. The system runs quietly and the CO2 levels stay steady. I’ve used it for over six months with no issues.