Having the best CO2 diffuser is essential for your aquarium plants to prolong and sustain a healthy life.

A CO2 diffuser kit breaks down large CO2 bubbles into smaller bubbles that are easy to dissolve. Plants then use this dissolved CO2 to prepare their food.

But choosing the best aquarium CO2 bubbler from the hundreds of options available in the market is a hectic task. To help you refine your search, we have compiled a list of the best ones you can buy in 2021.

What are we waiting for? Let’s jump to the list right away!

Comparison Chart

Product Diffuser Type Tank Size
JARDLI Pollen Glass CO2 Diffuser

Glass 20 Gallons to 50 Gallons
fibst CO2 Diffuser

Stainless steel 30 Gallons to 80 Gallons
Yagote CO2 Glass Aquarium CO2 Diffuser

Acrylic 15 Gallons to 50 Gallons

Aquario Neo CO2 Diffuser

Glass 30 Gallons to 80 Gallons

Review of Best CO2 Diffusers

1. JARDLI Pollen Glass CO2 Diffuser


  • It has a large ceramic membrane
  • Its U-shape connecting tube prevents CO2 blockage
  • 2 to 5 bubbles per second injection rate
  • Two suction cups add more grip


  • U-shaped glass is very small, which makes it difficult to install in a large tank

JARDLI Pollen Glass CO2 Diffuser is our champion in this competition. It has the most elegant glass design that blends seamlessly with your tank and makes it seem like CO2 bubbles are magically appearing out of nowhere. It is not only the best in looks but also in terms of efficiency.

It has a 1.5 inches wide ceramic membrane with very tiny holes in it. When the air is passed through these tiny holes, it breaks it up into very small bubbles that easily dissolve the CO2 in water. It’s so efficient that it dissolves up to 98 percent of the CO2 that is running through the membrane.

The U-shaped connecting tube acts as a bridge between the diffuser and the other tube that serves as the entryway for air. This setup ensures the free flow of CO2 without any blockage. This diffuser can produce at two to five bubbles per second injection rate, which is adequate for plants to prepare their food.

Installing the JARDLI pollen glass CO2 diffuser is very easy. It has two suction cups that stick the base of the diffuser firmly to the glass walls of your aquarium. Even though it is made out of glass, it does not feel fragile. However, it’s best to take precautions while handling it.


JARDLI Pollen Glass is the best-selling CO2 diffuser in the market for all the good reasons. It is durable, affordable, and is specially designed for tanks with 30 to 50 gallons capacity. So if you are looking for a reliable, long-lasting investment, this is the best option for you.

2. Fibst CO2 Diffuser for Aquarium


  • This is a stainless steel diffuser
  • Removable ceramic disc
  • Its high-quality metal clips add more grip
  • Friendly customer service


  • Works only in a high-pressure tank

If you are eying for a unique CO2 diffuser piece apart from the usual glass CO2 diffusers, then the fibst CO2 Diffuser for Aquarium is the one for you. This diffuser is a work of art and is made of 304 stainless steel. This diffuser requires a 7.5 PSI/0.5 MPa air pressure to generate air bubbles that quickly dissolve the CO2 in water.

The praise-worthy feature of this diffuser is that by turning the cup counterclockwise, you can remove the ceramic sheet for cleaning. This might not seem to be a significant factor, but after a few months of use, these diffusers end up collecting some dirt that is very hard to clean in standard CO2 diffusers available in the market.

As if building it out of steel instead of glass was not enough already, the fibst has put all the effort into making this diffuser as durable as possible. From the welds of the tubes to the quality of the ceramic membrane, every part of this diffuser reflects the quality.

One thing to keep in mind is to soak the diffuser in water for more than three hours. Initially, it tends to generate big bubbles if you don’t soak it, and it is completely normal. After 24 hours, the system reaches an optimal state, after which it generates smaller bubbles that dissolve easily in water.

You also get a 6-month warranty for the ceramic sheet and two years warranty for all the other parts of this diffuser. Being made of steel ends up being on the heavier side compared to the standard glass diffusers, making it a little challenging to attach it to the aquarium. To take care of that, the suction cup that holds it in place is not made of cheap plastic. Instead, it comes with a metal clip that holds the diffuser in place.


This stainless steel CO2 diffuser from fibst comes in three different sizes, making it ideal for tanks ranging from 10 gallons to 80 gallons. It stands superior to its competitors on the market by ensuring vigorous plant growth while still being affordable. If aesthetics are just as important to you as performance, this diffuser is a great pick.

3. Yagote CO2 Glass Aquarium CO2 Diffuser


  • It can be used with any CO2 system
  • Ceramic diffuser disc
  • Adjustable suction cup
  • It’s a see-through glass diffuser


  • You may experience occasional water leaks

Yagote has a reputation for coming up with great innovation and features in all the aquarium supply accessories they make. That said, they have now come up with a very unique and genius CO2 diffuser that can have the highest CO2 dissolving rates in the market.

To achieve this efficiency, they have created a spiral tube that revolves inside the ceramic chamber to ensure that the gas is finely mixed with water. Then it is passed through the atomic pores present in the ceramic diffuser that produces tiny bubbles. These bubbles rise slowly while dissolving the remaining CO2 in the water.

Made of high-quality glass, this inline CO2 diffuser is very strong and can survive minor shocks or drops. However, it’s best not to try your luck with anything made of glass. It has a beautiful see-through design that blends with the aquarium environment.

The suction cups make the installation process effortless. If needed, you can adjust its position by relocating the suction cups that attach the diffuser to the tank. This glass diffuser is compatible with pressurized tanks with a 15- to 50-gallon capacity.


Low prices on products are often seen as a sign of low quality. But it’s not the case with the Yagote CO2 diffuser. Its fair pricing makes it an excellent return on investment. If you are looking for an affordable and effective solution to diffusing CO2 in your aquarium, then this diffuser is a perfect choice for you.

4. Aquario Neo CO2 Diffuser


  • Has the finest bubble stream in this list
  • The diffuser is made of transparent acrylic
  • It comes with a simple design
  • It produces microbubbles


  • Slightly expensive for its size

If you are looking for a simple, little CO2 diffuser that can supply CO2 for fish tank without a hitch, then the Aquario Neo CO2 Diffuser might just be the one for you. It has the most simple design and no connecting parts.

The micro-holes present in the ceramic sheet are more capable of generating much smaller CO2 bubbles than its competitors. As a rule of thumb, the smaller the bubbles, the better the CO2 discharge. These tiny bubbles also ensure that your tank doesn’t get polluted easily. In addition, these microbubbles get dissolved in water faster than standard diffusers and help plants prepare their food.

You can easily install this diffuser in a few minutes and remove it from the tank for cleaning. Since the Neo diffuser is made of transparent acrylic, it won’t break easily like glass diffusers. So you don’t need to worry about separating it from the aquarium during the cleaning process.

This aquarium CO2 system will not only fit your budget. It also matches all aquariums sizes. It is ideal for tanks with 15 gallons to 60 gallons capacity. It is recommended to soak this diffuser in water for a few hours at least. By doing this, it functions better when fixed inside your tank.


The Aquario Neo CO2 diffuser generates more microbubbles per second than any other similar product in the market. It is not only effective, sturdy, and beautiful but also affordable. So if you are in search of a simple and elegant CO2 diffuser that doesn’t break your bank, then the Aquario Neo CO2 diffuser is a perfect choice.

A Comprehensive Buying Guide for the Best CO2 Diffusers

Here is a list of things that you must keep in mind to make the right purchasing decision. This checklist involves some common tank requirements that you have to factor in.

CO2 supply system: There are two types of CO2 supply systems: a compressed gas system and a bio CO2 system. The diffusers that break down this CO2 and dissolve it in your tanks require a constant high-pressure CO2 to work optimally.

That said, bio CO2 supply systems are not capable of generating high pressure. Even the low pressure which it produces might fluctuate largely. So if you still want to go for a bio CO2 supply system, make sure to use a low-pressure diffuser.

On the other hand, compressed gas systems deliver a constant supply of CO2 at high pressure. So choosing high-pressure diffusers for compressed gas systems is optimal. All the diffusers that we have mentioned in our list are suitable to sustain such high pressures.

Tank size: The next factor to consider is the tank size. The volume of water present in the tank determines the amount of CO2 gas required. In simple words, the larger the tank, the larger the diffuser should be.

If you want a CO2 diffuser for a large aquarium with over 100 gallons capacity, you can use two diffusers to supply CO2. It can be fixed on either side of the fish tank for a more even CO2 distribution.

If you put a large diffuser in a small tank, it might dissolve more CO2 into the water. This is good for plants but can be dangerous for fish. So make sure to check the compatibility of the diffuser with the fish tank by calculating the tank size.

Glass, acrylics, or steel: Picking the materials which the diffusers are made of is equally important. Mostly, all aquarium diffusers are made of glass or stainless steel and rarely acrylics.

The glass diffusers have a see-through design, and when immersed in water, it merges with it. Stainless steel diffusers are stronger than glass diffusers. They can be removed and cleaned without worrying about breaking the product. On the other hand, acrylic glass diffusers offer a mix of these qualities. They are transparent, affordable, and very sturdy.

Ceramic membrane quality: Go for a diffuser that has very fine pores in its ceramic membrane. The solubility of CO2 greatly depends on the quality of the ceramic membrane. The finer the pores of the membrane are, the better it can produce micro-fine bubbles.

The smaller CO2 bubbles dissolve faster in water than larger ones. This is because the smaller CO2 bubbles have a larger surface-to-volume ratio than larger bubbles. Thus, they get dissolved faster in water. However, keep in mind as well that a finer CO2 atomizer requires a high-pressure system.

Convenience and ease of usage: A diffuser must be easy to install, remove, and clean. Ceramic membranes are usually simple to maintain; all you need is a water and bleach mixture to clean them thoroughly.

Some models require the ceramic membrane to be replaced with a new one after some time. This ends up being an added expense. With that in mind, we have only listed the diffusers with reusable ceramic membranes as it requires less maintenance or no replacement at all.

CO2 Diffuser System FAQs

– What Does a CO2 Diffuser System Consist of and What Is Its Purpose?

A CO2 regulation system consists of a CO2 cylinder, a CO2 regulator, and the CO2 diffuser. The CO2 diffuser is an add-on with the primary purpose of dissolving the CO2 that comes from the CO2 regulator.

The CO2 diffuser is connected to one end of the bubble counter’s tube. And the tube’s other end is connected to the reactor. Now, the CO2 diffuser’s work is to break down the large bubbles that come from the bubble counter into tiny bubbles.

These tiny bubbles get quickly dissolved into the fish tank water and increases the CO2 level in water, which is then utilized by the aquarium plants in preparing food.

– What Are the Benefits of CO2 Diffuser for Aquarium?

Plants require CO2 to carry out photosynthesis even if they are inside the water. Naturally, CO2 exists in gaseous form. Yet, like oxygen is dissolved in water, we can also dissolve CO2.

To go about this process, we need the help of CO2 diffusers. A CO2 diffuser uses reactors or membranes to break down large CO2 bubbles into tiny ones to dissolve them in water easily. This increases the CO2 concentration inside aquariums, and the plants can thrive under this condition.

– Can an Excess of CO2 Kill the Fishes in Your Aquarium?

Yes, excess CO2 in water tends to harm your fish. When you fix a large diffuser for a small tank, it dissolves more CO2 into the water. When your fish tank has excess CO2, it makes it hard for the fishes to intake oxygen. So your fish might suffocate and die. That is why it is recommended to choose the right aquarium CO2 system for your fish tank.

– How Do You Clean the CO2 Diffusers?

The CO2 diffusers don’t require much maintenance. In fact, just like it is easy to install inside the tank wall, it is also easy to remove for cleaning. However, you must give special attention when handling glass diffusers.

Once you have removed the diffuser from the tank, use a mixture of water and bleach to clean it. After that, soak the diffuser in clean water for 24 hours before fixing it inside your fish tank again.


Aquarium plants demand a constant supply of CO2 for the photosynthesis process. A CO2 diffuser can help dissolve the CO2 in water by breaking down the large bubbles into smaller ones.

So a good CO2 diffuser is arguably one of the most important components that must be fixed in your aquarium to help the plants thrive.

If you only want the best for your aquarium, we strongly suggest you pick JARDLI Pollen Glass CO2 Diffuser.

This diffuser is very reliable and supports efficient CO2 atomization through its ceramic membrane. It is durable, reasonably priced, and creates a living environment for your aquarium plants. Additionally, it is hassle-free to install and maintain.

5/5 - (12 votes)


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