If you have live plants in your aquarium, they will need plenty of carbon dioxide so they can grow and thrive. However, you do not just stick a rubber tube connected to a CO2 tank and call it a day. You have to use the best CO2 diffuser aquarium to ensure that it gets properly dispersed in the water.
Although a hole immersed in the water can somehow diffuse CO2, it is still not quite efficient at doing so. The large bubbles would only float to the surface of the water and burst, causing most of the CO2 to only get wasted.
On the other hand, a diffuser will create thousands of tiny little bubbles that rise slowly, thereby giving them enough time to infuse the water with CO2. If you are thinking of using live plants inside your aquarium, you should also think about investing in a good CO2 diffuser to keep them healthy.
Best CO2 Diffuser Aquarium Reviews
1. Yagote CO2 Glass Aquarium CO2 Diffuser
This CO2 diffuser kit makes use of a durable and highly porous ceramic disc. This ceramic disc has hundreds of thousands of microscopic holes that make hundreds of thousands of tiny bubbles. With that, expect it to become more efficient at infusing the water with enough carbon dioxide to keep the live plants healthy.
Another thing I liked about this ceramic CO2 diffuser is that it uses ultra-clear glass material for its construction, making it almost invisible when placed in the tank. It is also quite small, so it is easy to hide behind the live plants and other tank decorations. I used this in a small 15-gallon tank and you would not even notice it.
This is also quite easy to install. You do not even need any kind of tools for the installation process. This diffuser comes with two small suction cups that let you attach the diffuser snugly on the corner of the tank. Once the suction cups take hold, you can rest assured that the diffuser will not be going anywhere.
Another thing that I liked about this diffuser is that it has such a curved design that it can significantly slow down the flow of the water, much like the more expensive Fluval CO2 diffuser. This allows more carbon dioxide to infuse into the water compared to other diffusers that make fewer and bigger bubbles.
I did not have any problems whatsoever with the product I received. However, I discovered several negative reviews about their aquarium CO2 diffusers. Most said that the ceramic disc in their diffusers was not as porous as advertised. Some even said it caused massive backflow, a result of poor quality control on the manufacturer’s part.
2. JARDLI Pollen Glass CO2 Diffuser
This diffuser comes with a ceramic disc that is so porous that it can produce hundreds of thousands of tiny bubbles when connected to a carbon dioxide tank. With that, the device can efficiently infuse the water with enough carbon dioxide to keep your live plants healthy and thriving.
This diffuser also comes with a U-shaped connector. This part prevents blockages in the air line. This extends out of the tank before connecting to the rubber hose from the CO2 tank. With that, you no longer have to deal with the aftermath of not giving your live plants enough CO2 during the night.
Even though this device is so small, it is still one fantastic option for suitable CO2 diffuser for a large aquarium. Even the live plants on the far side of your large tank will be getting more than enough carbon dioxide to keep them healthy. If you will be using this in a smaller tank, you only need to lower the pressure.
I also like that this diffuser is so crystal clear. This allows the device to blend into the tank environment almost seamlessly. Aside from that, this makes it a whole lot easier to hide behind the tank décor so that your aquarium will not look like a still with all the tubes and pipes going into it.
A word of warning though: be very careful when cleaning this glass diffuser as it is quite fragile. I was already quite careful when I was washing my diffuser, and yet it still broke into two pieces and cut up the palm of my hand in the process. You should be very careful when handling this diffuser as it makes use of very thin glass for its construction.
3. Aquario Neo Co2 Diffuser
Unlike most of the other carbon dioxide diffusers in the market right now, this product uses acrylic. This material is almost as clear as glass, but it is not nearly as fragile. You can be as heavy-handed as you like when cleaning or installing this device, unlike the glass ones that are so fragile that they would shatter if you so much as sneeze on them.
The Aquario Neo CO2 diffuser uses a ceramic diffuser like most of the other carbon dioxide diffusers available. I am quite impressed by how tiny and uniform this diffuser can create bubbles. This was so efficient that I had to turn down the tank’s regulator as the diffuser made the CO2 saturation a bit too high.
Even though this is not as clear as the glass diffusers, this product is still quite transparent, which makes it easy to hide in the backdrop of your aquarium tank. I placed mine in the far corner of my tank behind some plants, and you would not even notice where they are if I did not tell you where to look.
I use my diffuser on a rather small tank, around 15-gallons capacity. However, I do not doubt that this would work well in an aquarium that is several times bigger than the one I have. The manufacturer mentioned that this diffuser is ideal for use on tanks as large as 75-gallons capacity.
I do have a bit of an issue with the diffuser leaking a bit. Around the lip of the ceramic diffuser, there are some points wherein the CO2 leaks a bit. The bubbles coming out are still a bit on the small side, so you can probably ignore this.
4. Bluecell Aquarium CO2 Diffuser
If you have high-tech live plants in your tank, then you will love this diffuser because it comes with a built-in bubble counter. It will tell you if the diffuser is dissolving too much carbon dioxide in the water, which might be good for your plants but will kill your fish.
Just like the other carbon dioxide diffusers available, this one is quite easy to install. You just need to connect the silicone hose carefully to the glass and use the included suction cup to place it anywhere you like in the tank. Do keep in mind that the deeper you place the diffuser, the higher the CO2 pressure needs to be.
You do not have to worry about the air line getting pinched when it drapes over the edge because this Starside aquarium co2 diffuser comes with a glass U-shaped tube. This will make sure that there will always be a continuous supply of CO2 for your plants whenever they need it.
Although this glass diffuser is a bit on the fragile side, it can withstand up to 30 psi of pressure. This means that even though it is small, you can step up the gas pressure so that you can provide enough CO2 even for a large 75-gallon tank.
With that said, you do need to use somewhat high gas pressure to push the CO2 out of the diffuser. This means that this will not work when you are using a DIY setup as it might not produce enough gas pressure to push the CO2 through the diffuser.
5. Zerone Stainless Steel Carbon Dioxide Diffuser
One of the things that I liked about this diffuser is that it uses sturdy stainless-steel tubing. This means that this diffuser, unlike the usual ones made of very thin glass, can withstand dropping. You can also clean it thoroughly without it shattering in your hands.
This has a U-shaped design that allows you to hang the diffuser over the edge of your tank. This design will prevent the air line from pinching and stopping the flow of carbon dioxide. However, it will only fit over the edge of rimless tanks, so if you have one of those old-fashioned tanks, you may need to make slight modifications to your tank.
Another nice thing about this product is that you can completely dismantle it for thorough cleaning. You can even remove the ceramic disc and replace it when needed. It is not like glass and acrylic diffusers where the ceramic disc is glued onto the body of the diffuser.
Even though it is a small device, it can dissolve enough carbon dioxide for a large 75-gallon capacity tank. However, you do have to open the tank completely. I suggest that you use at least two of these diffusers, placed at opposite ends of the tank for more efficient diffusion of carbon dioxide.
There is a bit of a problem though. The seal around the ceramic diffuser deteriorates rather easily. After just a couple of weeks, I noticed large bubbles coming out of the edges of the diffuser, but just one or two every so often. I had to find a beefier O-ring to replace the flimsy one that came with the set.
6. TWINSTAR CO2 Diffuser
Even though this diffuser is completely clear, it is not made of glass. This device makes use of tough, shatter-proof acrylic for its construction. Although it is still not quite as clear as glass, this, at least, would not break into pieces if you ever get a bit overzealous while cleaning it.
Another neat feature of the Twinstar CO2 diffuser is that it uses an efficient ceramic microspore diffuser disc. The bubbles that this diffuser makes are so tiny that you cannot even discern the individual bubbles. It looks like there is a plume of white smoke coming out of the stone.
Because the bubbles this diffuser makes are so tiny, they linger much longer in the water. Because of that, the carbon dioxide has more time to dissolve into the water. With that said, you need to be careful and monitor the CO2 saturation of the aquarium as it might get a bit too high.
Since most of the parts of this diffuser are made of acrylic, you can be a bit rougher when assembling and installing this device. This also comes with a strong suction cup so you can position it at the bottom of your tank securely. Note that if you have trouble connecting the air line to the device, soak it in the water for at least half an hour first.
I do not have any serious complaints about this device, but I did notice that there is a slight leak in the connection between the ceramic disc diffuser and the main body of the device. However, this is not something that warrants a return of the device. I managed to fix the leak using a couple of drops of super glue along the seam.
7. FZONE Glass Inline CO2 Diffuser
Unlike the usual CO2 diffusers that you find in aquarium stores, this one does not go into the aquarium. It connects onto the return tube of a sump. This allows the carbon dioxide bubbles to circulate better inside the aquarium. It also makes this diffuser ideal for large planted tanks.
This inline CO2 diffuser also comes with suction cups so you can mount them on the side of your tank. Why would you want to do this, you ask? Because this blown glass piece is quite pretty and so you can monitor how much carbon dioxide is introduced into the tank. You can also just mount this inside the sump cabinet to keep it out of sight.
Another benefit of not placing the ladder CO2 diffuser inside the tank is that it makes cleaning and maintenance a lot easier and less frequent than before. However, you will still need to inspect it every so often to make sure that it is clean and working properly.
Moreover, since the diffuser is not even in the water, you do not need to arrange your décor to hide the diffuser. That is if you want to give your tank a more natural look and feel.
Here’s the catch, though. Because the diffuser is quite tiny, you will need to use a carbon dioxide tank system to provide the gas. A DIY soda bottle carbon dioxide reactor will not create enough pressure for this to work as efficiently as possible.
8. AQUATEK CO2 Diffuser
One of the best features of this diffuser is the built-in check valve. This will protect the rest of the CO2 system against backflow. It usually happens when the system is open when the CO2 tank is empty. Since there is no carbon dioxide pushing the water out of the diffuser, water will flood inside the diffuser’s tubes.
Don’t think that because of this device’s compact size that it is not efficient at dissolving carbon dioxide into the water. If there is enough gas pressure, this small diffuser can increase the CO2 saturation of the water to the ideal level much faster than some larger devices.
Another nice thing about this product is that the ceramic diffusers are replaceable. This means I do not need to clean the ceramic disc if it gets too dirty or clogged with algae. I have tried cleaning ceramic diffuser disks before and it is not that easy to do.
This is also quite easy to install. You just need to insert the hose from the CO2 regulator into the inlet of the diffuser. This device also comes with two strong suction cups, which means you can securely install it right in the corner of the tank.
As mentioned earlier, the ceramic disk that came with the diffuser is kind of hard to clean. However, you will still need to do so every week to ensure that it works properly. Other than this small detail, I cannot find anything else to complain about this product.
9. Hygger Aquarium Air Stone Kit
This product is technically not a carbon dioxide diffuser. It is an air stone but a fancy one at that. The difference between this and a regular planted tank CO2 diffuser is that it has a wider surface. The air is also pumped evenly around the stone so that it somewhat evenly produces bubbles all over its surface.
In addition, since this is an air stone, it is heavy enough that it holds itself down under the surface of the water. I just dropped it in the water and maneuvered it into position.
Even when I turn on the CO2, the airstone does not move from its position. However, if you want it to stay put, you can use the suction cups underneath it to fasten the air stone on the base of the tank.
Because of its large surface area and the fine porosity of the ceramic diffuser when you turn on the gas, you will get a lot of tiny bubbles coming out of the surface. However, since the air stone is at the bottom of the tank, you have to open the CO2 tank quite a bit to send enough gas into the air stone.
Although this air stone is not as efficient, it is multiple times more durable and infinitely stronger than flimsy glass diffusers. Even if you accidentally drop this on the floor during installation or maintenance, it would barely get a scratch.
However, as mentioned above, this product is not a true CO2 diffuser. You can just use it as an alternative due to the absence of the real thing. The bubbles that this air stone produces are not small or numerous enough to attain even 50-60% efficiency, so you will be wasting quite a lot of CO2s.
10. PIVBY U Shape Aquarium CO2 Diffuser
This CO2 diffuser might look like regular glass, but it is made of resin glass, which is significantly tougher and more break-resistant. You do not have to be overly careful when handling and cleaning this device. You will need to deliberately put too much force on it for it to break.
I always feel nervous when attaching the air lines on a regular glass carbon dioxide diffuser because they are so delicate. One wrong move and it will break in half. This is not a problem with this device. When I held it in my hand, it felt heavier and more durable so setting it up was not quite nerve-wracking.
This diffuser also comes with a check valve. This will prevent water from getting into the diffuser and the CO2 system if you accidentally let the tank get empty. The valve will automatically close if there is not enough gas pressure coming from the tank.
I also liked how much care was taken in manufacturing this product. The seams are air-tight and the diffuser stone has just the right porosity to create a good number of micro-bubbles. The bubbles are so small and so many that they look like a wisp of smoke coming out of the diffuser.
However, as much as I love this device, I did not like the small U-shaped connector. The reason is that I have a rimmed tank and the connector is not wide enough to go over the edge. I needed to use my Dremel to cut off a piece of the rim just to make this diffuser fit on my tank.
What to Look For When Buying a CO2 Diffuser Aquarium
If you are a beginner aquarist, and this is your first time trying out a planted tank, then you most likely do not know what to look for when shopping for a carbon dioxide diffuser. If so, then here is a quick buying guide that will teach you the basics.
You need to know how much gas pressure the diffuser needs to create micro-bubbles. This means that if you are planning to use a DIY soda bottle reactor, then you need to look for a diffuser that can work even with low gas pressure.
Now, if you are going to use a regular CO2 tank, then you are probably okay using any of the diffusers that you can find.
Ease of Installation and Maintenance
You should know that keeping live plants is not that easy. Aside from all the regular maintenance tasks that you must do for your aquarium, you will be adding more tasks to your to-do list. If you will be getting a carbon dioxide diffuser, make sure that it is easy to clean and maintain.
Strength and Durability
Most of the diffusers that you will find in the market are made of glass and thin and fragile glass at that. I have gone through quite a lot of glass carbon dioxide diffusers because they were so delicate.
If you want something more robust and durable, then you should stay away from glass diffusers and find ones made from acrylic or stainless steel. You can also check a Seachem CO2 diffuser review to check if their products are right for you.
To avoid wasting CO2, you need to use an efficient diffuser. You can tell how efficient a device is by the size of the bubbles that it produces and how long those bubbles linger under the surface of the water. Smaller bubbles allow for the more efficient dissolution of the CO2 gas in the water.
Some diffusers are so efficient that they can dissolve almost 100% of the gas into the water. This means there are hardly any bubbles reaching the surface and popping.
Frequently Asked Questions
Do I Need a CO2 Diffuser for my Aquarium?
If you are using fake plastic plant decorations, then it would be unnecessary for you to use a CO2 diffuser. You will only need a diffuser if you have real plants in your tank. Real plants need carbon dioxide to flourish and if there is not enough CO2 dissolved in the water, your hydrophytes will not survive.
How to Clean an Aquarium CO2 Diffuser?
First, you need to turn off the CO2 supply. Next, carefully disconnect the diffuser from the air line and remove the device from its mounting position. Place the diffuser in a plastic container that is just barely big enough that you can place the device on the bottom.
Prepare a 50/50 solution of bleach and water. Submerge the diffuser in the said solution for at least 30 minutes and then rinse the entire thing with clean tap water.
You should avoid touching the ceramic diffuser as your skin oils might clog up the tiny holes in the diffusers, thereby negatively affecting its efficiency. Also, do not scrub the ceramic diffusers as this will only push dirt and debris into the pores.
Keeping an aquarium with live plants can be quite challenging, especially if your plants have high CO2 requirements. If you are serious about keeping live plants, then you need to invest in the best CO2 diffuser aquarium that you can find.
This will ensure that your plants are getting more than enough carbon dioxide to keep them healthy and thriving.