How to Set Up an Aquarium CO2 System the Easy Way

Have you wondered how to install the CO2 System in your aquarium? This is not reserved for professionals! The convenient and easy way of installing the CO2Art equipment is for everyone that wants to enrich their aquascapes with this game-changing gas!

Why to inject CO2?

Firstly, we need to underline how beneficial the CO2 injection is. Even not demanding aquarium plants with CO2 injection can look totally different than ever before. Deeper colouration, healthier look and compact growth? CO2, lighting and ferts can make your scape look like from the aquascaping contest, not a beginner's tank!

This is because of the photosynthesis that is supported by the CO2 injection. In underwater conditions, the CO2 concentration is muuuuch lower than in the atmospheric air. Therefore aquatic plants need to struggle a bit to produce their own food through this process. Although there are ferts like “liquid CO2”, the effect is not as impressive as in case of pressurised systems. Providing your plants with a regular day and night cycle and constant CO2 injection has much better results than occasional CO2 feeding. In this article we are going to present you how easy the installation is and what should you pay attention to.

Gear selection

Before installation, selecting the right CO2 aquarium setup is crucial. Even the most expensive gear if not selected according to your aquarium’s needs can be not efficient. 

CO2 cylinder

CO2 bottle is a must have which is obvious. Pub bottles, CO2 fire extinguisher, Sodastream, Paintball, Disposable Bottle or cylinders from any industrial gas company (such as the British BOC) will all work. The cylinders are equipped with a standard specification valve assembly mounted to the neck of the cylinder, to which the CO2 regulator can be mated. Specialist type bottles, such as paint gun bottles require an adapter.

CO2 Accessories


The most important product in terms of safety and efficient system operation is the CO2 regulator. In our offer you will find 2 models of CO2 regulators that are both dual stage and super durable (which is confirmed by the 5 and 10 years warranty!). The solenoid attached to the regulator assembly allows automatic turning on and off of the gas.

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

Find our bestseller! The PRO-SE CO2 Regulator


The CO2 regulator is equipped with two gauges: the right one shows the amount of gas present in the CO2 cylinder and the left one shows the working pressure that is pushing CO2 to the diffuser. The dual stage construction means that you will avoid the end tank dump which means degassing fauna. Also both regulators are equipped with a bubble counter with an in-built check valve preventing the water back flow and regulator damage. Simple design, maximum reliability and high quality materials are the factors making these regulators total best-sellers. Visit our regulator comparison chart to see the difference between our two stars! 


The next product that is super important is the diffuser. This device is responsible for the efficient gas solution in the aquarium water. It’s usually equipped with a ceramic membrane and the gas coming through its porous surface is readily dissolved in the aquarium.

However, for the optimum operation of the CO2 system, the ceramics should be cleaned or replaced regularly because a clogged membrane may lower the gas injection. In our offer you will find replacement membranes dedicated to our New Inline Diffuser and IO Acrylic and Stainless Steel Series Diffusers. This is an extremely convenient way of keeping the ceramic clean and delivering CO2 to the aquarium without a pause. 

Depending on the filtration system you have, you can choose an inline or in-tank diffuser

Acrylic Series - In-Tank CO2 Diffuser


An Inline Diffuser is designed to be used with an external filter. Contrary, the in-tank diffuser can be used with various internal filters, HUB filters and... External filters too. If you’re interested in professional advice on the gear from our Expert Team, feel free to contact us anytime via

CO2Art Inline CO2 Aquarium Atomizer Diffuser System

Inline Diffuser by CO2Art: Find the offer under this LINK


Visit our collection of the CO2 accessories that are used by thousands of aquascapers around the world, making their scape look classy and elegant. You will find them under this LINK.

Must-have items

Of course, there are some super necessary accessories that every aquarium owner should have! 

The first thing is the drop checker. It’s a glass vessel placed inside the aquarium opposite to the CO2 source. The reagent inside reads the CO2 concentration inside the aquarium. The target is a deep green colour which means that the right amount of CO2 is being delivered to the aquarium. Drop checker should be observed to apply any adjustments on the regulator if necessary. Visit our article about 7 Things You Need To Know about Drop Checkers to see more details about its science. 


Another thing that needs to be added to the Complete CO2 System is a CO2 resistant tubing. And this is not accidental. It’s recommended to use ONLY CO2 resistant tubes for CO2 injection as the silicon tubing may cause even tiny leaks and become brittle after a short time of usage. 



Ok, let’s say the gear is now selected. Let’s move to the installation and let’s see how easy CO2 for aquarium can be!

The only tool you need is an adjustable wrench. 
  1. Make sure the CO2 cylinder is turned off, the regulator front knob is turned fully anticlockwise and the needle valve is closed. 
  2. Connect the tank to the regulator stem and tighten it with an adjustable wrench. 
  3. Turn on the main tank valve (you will see the reading on the right gauge only)
  4. Turn on the front knob to about 40 psi on the left gauge (if used with CO2Art diffuser)
  5. Switch the solenoid on
  6. Slowly open the needle valve and set the desired bubble rate. Change if necessary according to the drop checker reading after a few hours. 
Ok, so the regulator is ready! Visit our support portal where you can find all the manuals!

What will you see after installation?

  • Fast growing aquarium plants with CO2 injection
  • Healthier look of the plants
  • Vivid colouration of the leaves 

If you're wondering how to set up a planted aquarium with CO2 from the very beginning, visit out old but gold article explaining all the elements in detail! LINK

Remember that CO2 injection means a supported process of photosynthesis which should go hand in hand with the light intensity. If you already have low light aquarium plants with CO2, the injection should be adjusted to the lighting, not opposite. 

Another thing to remember is that while adjusting the bubble rate, we should start with 1-2 bubbles per second and make any other adjustments after a few hours  according to the drop checker colour. 

Placement of the diffuser

Placement of the gear is another super important point in CO2 setup for planted aquariums. In case of in-tank diffusers, they should be placed under the filter outlet so the clean water mixes with CO2 while entering the aquarium and travels around it until it’s sucked by the filter inlet. The water flow plays a very important role here. Too strong water flow may cause the gas to rise quickly to the surface, not reaching the plants. On the other hand, too weak water flow doesn’t mix the water with CO2, not delivering the gas to every corner of the aquarium. Everything is a matter of experimenting therefore having a hi-tech setup requires our patience and engagement.

As to the Inline Diffusers, the installation is shown on the video under this LINK. It doesn’t matter what direction is used. In case of this diffuser, the drop checker should be also placed opposite to the filter outlet. 


Putting everything together, installation of the CO2 System made by CO2Art is an extremely easy task. With our Complete CO2 System planted tank community was never more satisfied. If you have a fish tank CO2 system is also for you!  Did you fail with any demanding plant? Give it another chance on the high-tech site. This is all about this fantastic hobby: it has many ups and downs but we all have the same aim: a successful planted aquarium full of happy fish and lush greenery.  One thing is certain: with CO2 injection aquarium plants are definitely different.

Do you have any additional questions? Feel free to contact us via!