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Why do we need CO2 in the aquarium?

In a planted aquarium, CO2 is the one nutrient the water cannot supply on its own. Inject it steadily and plants pearl, colours deepen and algae loses its head start.

CO2 for beginners

Build your CO2 system

Seven questions about your aquarium, your cylinder and your filter, and you end with a system whose parts are made to fit each other. The price is the sum of the parts.

Build your system Or take a ready-made kit

CO2Artists

A growing family of the world's best aquascapers, all proud to put CO2Art equipment at the heart of their work.

Meet the artists

Tag your aquarium #co2artartist — every tile is the creator's own post, credited and linked.

Dual-stage regulators

Pro-SE or Pro-Elite?

Both are dual-stage, so the pressure does not surge when the cylinder runs low, the fault single-stage regulators are known for. The difference is how much pressure they give you, and how steadily they hold it.

PRO-SE Series - Aquarium CO2 Dual Stage Regulator with Integrated Solenoid

Pro-SE

£145.00

Max pressure
40 PSI2.7 bar
Holds pressure to within
about5 PSI
Best for
Most planted aquariums.
View product
New Pro-Elite Series V2 - The Most Advanced Aquarium Dual Stage CO2 Regulator

Pro-Elite V2

£243.00

Max pressure
80 PSI5.5 bar
Holds pressure to within
about1 PSI
Best for
Several aquariums off one cylinder, manifolds, and the steadiest bubble count.
View product

What aquascapers say

4.8/5

across 2,000+ reviews

Read all reviews
  • 50,000+aquascapers worldwide
  • 60+countries shipped to
  • 13+years of aquarium CO2

Appareil mis rapidement sur ma bouteille de CO2, raccordements effectués et réglages lancés. La molette de réglage de pression est un peu dure mais j'y suis arrivé. A ce jour, tout fonctionne parfaitement.

Denise E.Verified buyer Orange, France

Great service, fast shipping and easy to set up. I got the full CO2 system and cannot be more happy!

Nadezda S.Verified buyer Dublin, Ireland

The pleasure to see very fine bubbles from an original and tiny diffuser.

Emmanuel V.Verified buyer Toulouse, France

Great little difusor for my aquarium. Bubbles are super small, almost like the mist. Dont think there is any better then this!

RobertVerified buyer Zagreb, Croatia

That's a great device to help kick-off plants, works amazingly well with SodaStream adapter bought separately. My 110L is thriving after just one week with it.

Mohamed A.Verified buyer Genève, Switzerland

Complete kits

Regulator, diffuser, tubing, drop checker and the small parts, made to fit each other. Pick by regulator and by diffuser.

Pro-SE Series Complete Aquarium CO2 System with in-tank Flux_ Diffuser Pro-SE with in-tank diffuserPRO-SE regulator + Bazooka Flux diffuser£201.00 Pro-SE Series Complete Aquarium CO2 System with New Inline CO2 Diffuser Pro-SE with inline diffuserPRO-SE regulator + inline diffuser for the filter hose£210.00 New Pro-Elite Series V2 Complete Aquarium CO2 System with in-tank Flux_ Diffuser Pro-Elite with in-tank diffuserPro-Elite V2 regulator + Bazooka Flux diffuser£298.00 New Pro-Elite Series V2 Complete Aquarium CO2 System with New Inline CO2 Diffuser Pro-Elite with inline diffuserPro-Elite V2 regulator + inline diffuser for the filter hose£307.00

Prefer to choose part by part? Build your system.

Best sellers

The regulators, diffusers and drop checkers most aquascapers start with.

4.6

PRO-SE Series - Aquarium CO2 Dual Stage Regulator with Integrated Solenoid

£145.00
4.7

CO2Art Inline CO2 Aquarium Atomizer Diffuser System

From £43.00
5.0

NEW IO Diffuser - Acrylic Series - In-Tank CO2 Diffuser

From £18.00
4.7

In-Tank Bazooka Flux_ CO2 Diffuser for Planted Aquariums

From £25.00
4.2

New Pro-Series CO2 Adapter for Paintball - Sodastream - Disposable

£25.00
4.8

New Pro-Elite Series V2 - The Most Advanced Aquarium Dual Stage CO2 Regulator

£243.00

Instagram

Follow us on Instagram

Follow @co2art

Instagram post by @co2art @co2art CO2ArtThe secret to those vibrant reddish-orange stems? Consistent CO2. Our Flux_ diffuser helps nourish your plants, bringing out their brightest colors. 🌱20 Sep 2026 Instagram post by @co2art @co2art CO2ArtInspired by nature's quiet brilliance. Just as light nourishes this forest's lush moss, precise CO2 delivery with our SS-Series empowers your aquatic plants to thrive, creating breathtaking underwater worlds. ✨18 Sep 2026 Instagram post by @co2art @co2art CO2ArtThe pristine vitality of this stream, from its gentle flow to the life-giving droplets. Our precision CO2 check valve helps you bring that same vibrant ecosystem to your planted tank, nurturing every lush fern. 🌿💧17 Sep 2026 Instagram post by @co2art @co2art CO2ArtThose delicate pearling bubbles are a beautiful sign of a happy, photosynthesizing aquascape. Our CO2 Drop Checker helps you maintain the perfect balance for such vibrant life. ✨16 Sep 2026 Instagram post by @co2art @co2art CO2ArtThe golden light filtering through the forest whispers of life nurtured. Just like this tranquil scene, a thriving aquascape is rooted in balanced CO2, effortlessly enabled by a Flux diffuser. 🌿✨15 Sep 2026 Instagram post by @co2art @co2art CO2ArtA different angle, a whole new perspective. 👀15 Sep 2026 Instagram post by @aquascaping.passion @aquascaping.passion CO2ArtJEU CONCOURS AVEC CO2 ART14 Sep 2026 Instagram post by @co2art @co2art CO2ArtThe quiet power behind your aquatic forest. Just as nature thrives with essential elements, our solenoid ensures your planted tank flourishes with vital CO2. Look at this vibrant moss – imagine that same life in your tank. 🌿13 Sep 2026
 

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