Aquario Neo CO2

A bacterial CO2 generator that gives small-to-medium planted tanks a steady CO2 boost — no pressurised gas, no regulator, and a proper step up from a homemade sugar-and-yeast bottle.

CO2 (carbon dioxide) is the gas plants feed on, and adding more of it speeds plant growth — high-tech setups inject it from a pressurised bottle through a regulator (the valve gear that meters the gas out). The Aquario Neo CO2 skips all of that: it runs on a stabilised Saccharomyces cerevisiae (yeast) culture held in a nutrient-jelly cartridge, not a pressurised cylinder. Fermentation happens right at the jelly-to-water interface, which is the trick that sets it apart from a DIY bottle rig — output stays steadier over the cartridge's life instead of surging in the first few days and tapering off from there — that's Aquario's positioning versus a DIY rig, not a comparison we've independently tested.

It's built for roughly 10–30 US gallon tanks (approx. 38–114 L), and each bio-cartridge is rated for around 50–60 days before it needs replacing, depending on how warm your room runs. The kit comes complete: hose, diffuser (the piece that breaks the gas into fine bubbles so it dissolves in the water), cap, and one bio-refill cartridge to get you started.

Worth being upfront about what this is and isn't. It's a genuine, no-fuss CO2 boost for a nano (very small) or small planted tank — no pressure vessel, no regulator, no bubble-counter fiddling (the little chamber used to count gas bubbles per second on bottle systems). It is not a substitute for a full bottle-and-regulator CO2 system if you're running a larger tank or CO2-hungry high-tech plants — species that only really thrive with injected gas; output is modest by comparison.

One naming note, because the two get mixed up: this Neo CO2 is a bacterial CO2 generator, not to be confused with Neo C — Aquario's dechlorinator/water conditioner (the product that makes tap water safe), stocked separately in our Water Conditioners collection. Similar names, completely different jobs.

• Bacterial (yeast-culture) CO2 generation in a nutrient-jelly cartridge — no pressurised gas, no regulator
• Steadier fermentation than a DIY sugar-and-yeast bottle, thanks to jelly/water-interface fermentation — not independently tested against a DIY rig
• Suits roughly 10–30 US gallon tanks (approx. 38–114 L)
• Bio-cartridge rated approx. 50–60 days, depending on room temperature
• Kit includes hose, diffuser, cap and one bio-refill cartridge
• Not the same product as Neo C (our dechlorinator/water conditioner) — similar name, different job, different collection