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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 Get the e-book · $20.00

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 1,100+ reviews

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

I last used CO2 approximately 10 years ago. This regulator with integrated solenoid is amazing! Setup is easy. Once you get it setup, you are set. I do recommend getting a timer to plug the solenoid into so you will not choke out your livestock. My red plants are actually red, and my carpet is taking off.

Gabe I.Verified buyer Lake Station, Indiana

Easy to install or replace. Lasts about 2-3months before needing to be cleaned or replaced

Kevin P.Verified buyer Anniston, Alabama

Excelente producto, la graduación del cuenta burbujas es muy fácil al igual que la presión de salida, el servicio al cliente en el seguimiento del envío y la recomendación del bloque de salida compatible para mi nuevo regulador perfecto. Es de lejos el mejor regulador que he comprado.

RubénVerified buyer Envigado, Antioquia

Overall, great regulator would buy again. An upgrade to my My Fzone regulator. Great bubble control. My biggest issue with it is, the behemoth of power plug it comes with. It's universal international power plug.

MikeVerified buyer Lakewood, Washington

Just recently installed - first ever c02 experience in my planter tanks - couldn’t have been easier - quality components that is easy to notice

RandyVerified buyer River Ridge, Louisiana

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$209.95 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$329.95 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 USA CO2 cylinder does not run out quietly.11 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USEvery ripple you add to the surface costs you CO2.9 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USMost of the eels in freshwater tanks are not eels at all.8 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USYour drop checker is an hour or two behind your tank.7 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USHow many bubbles per second does your planted tank need?3 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USYour fish breathe out CO2 all day — is that enough for your plants?2 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USOne more weekend to get your scape photographed.1 Oct 2026 Instagram post by @co2art_us @co2art_us CO2Art USThose tiny bubbles streaming off your leaves in the afternoon have a name: pearling.30 Sep 2026
 

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