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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

$149.99

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

Pro-Elite V2

$269.99

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 950+ reviews

Read all reviews
  • 20,000+aquascapers worldwide
  • 60+countries shipped to
  • 13+years of aquarium CO2

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

Nadezda S.Verified buyer, Ireland

Best Regulator I ever had. Easy to handle and very good quality. Set it up together with a CO2 Inline diffuser and the Check valve from co2art. Highly recommend to use all these parts together.

Alex C.Verified buyer, Germany

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, Switzerland

Excellent! With very high atomization of CO2 it becomes very effective. Highly recommend it.

Håkan E.Verified buyer, Sweden

Very fast service, easy to install and you get the perfect size of bubbles, like dust!

George G.Verified buyer, Cyprus

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$214.95 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$221.96 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$334.95 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$341.96

Prefer to choose part by part? Build your system.

Best sellers

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

4.5
Save 17%

In-Tank Flux_ CO2 Diffuser V2

Sale priceFrom $23.99Regular price $28.99
4.7

CO2Art Inline CO2 Aquarium Atomizer Diffuser System

From $45.99
4.9
Save 38%

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

Sale priceFrom $19.99Regular price $31.99
4.1

NEW IO Diffuser - Stainless Steel Series - In-Tank CO2 Diffuser

From $46.99
4.8

NEW CO2 Drop Checker Kit - CO2 Concentration Monitoring Set

$18.99
4.6
Save 32%

New Pro-Series Precision CO2 Check Valve

Sale price$12.99Regular price $18.99

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Instagram post by @co2art_us @co2art_us CO2Art USThe forest's golden hour beautifully illuminates this vibrant moss and fern, reminding us of nature's perfect harmony. Our NEW Precision SS-Series helps you replicate that essential balance, ensuring your aquatic plants thrive in a lush, tranquil aquascape. 🌿20 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USJust as these sun rays awaken the forest, our Precision SS-Series gently nourishes your planted tank. Cultivate nature's vibrancy, right in your home. ✨18 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USSmall bubbles, efficient CO2 diffusion. 💨🌱18 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USJust as nature finds balance, our suction cups ensure your equipment is discreetly secured. This allows your aquatic ecosystem to thrive and your plants to reach for the light, as beautifully as these sun-drenched forest trees. 🌳17 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USThis vibrant green carpet thrives thanks to precise CO2 delivery. Our PRO-SE Series regulator helps orchestrate the perfect conditions for your aquascape to flourish, bringing that lush beauty to life. 🌱16 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USThe secret to a lush, thriving aquarium? It's often the unseen balance. Our CO2 Drop Checker Solution helps you mirror nature's perfect harmony, allowing your aquatic ferns to unfurl as vibrantly as these, sparkling under the gentle light. ✨15 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USFound the perfect piece of wood on a forest walk? Or a rock that would look amazing in your aquarium? 👀15 Sep 2026 Instagram post by @co2art_us @co2art_us CO2Art USThat lush, healthy moss on the wood? It's all about providing the right conditions. With our Precision Pro-Series, you're giving your plants the exact care they need to thrive beautifully. 🌱13 Sep 2026