Best Aquarium CO2 System That'll Keep Your Tank Healthy

Best Aquarium CO2 System That'll Keep Your Tank Healthy

13 min read

Today, we will dive into learning a few things about aquatic plants. Since the product we will discuss in this article directly relates to aquatic plants. If I said it was engineered to meet the needs of aquatic plants, I would not be mistaken. Here, we will share facts and information that helped you choose a CO2 aquarium system that meets your needs exactly. More often than not, people buy expensive systems only to realize later that they are optional.

Yes, many individuals to this day think, CO2 is what only aquatic plants need to survive. But don't be shocked when we tell you that aquatic plant growth requires water, sunlight, and CO2, just like our Terrestrial plants require for photosynthesis. So simply putting CO2 in your aquarium only solves some of your problems.

You should compliment your CO2 with proper aquarium lighting and create flow in your tank. Alone, CO2 systems cannot provide you with a healthy aquarium tank. We have written some key points to help you make an informed decision before selecting a CO2 aquarium system. Again, while choosing, we want to emphasize that it is a team game, and you must consider the other factors.

How We Choose the Best Aquarium CO2 System

Our selected planted aquarium CO2 systems are based on cater to small to medium-sized fish tanks ideally. But the main reason for this article is to guide you on how marine life operates and how you can get the most out of your CO2 system.

We first looked at the cylinder of the system that it comes with. The cylinder's quality and size matter most. It is essential to have easy and safe installation, as any leakages could be highly fatal. After that, we checked on the regulator of the system. The regulator is the one that manages the speed of flow of gas pumping inside the tank. Always try to go for a system that has a solid-built regulator.

Then, to make our system effective and efficient, a diffuser is a must. The smaller the bubbles, the better that diffuser is. Next, monitor the carbon dioxide level inside the aquarium, and the system should have a bubble counter. Finally, a solenoid valve with an automatic 24h timer helps you save from wasting unnecessary gas.

1. ZRDR Aquarium CO2 System

This system is one of the most reliable CO2 generators for fish tanks on the market. The durability of this CO2 system comes from its stainless steel build. In addition, its overall layout and functionality erase all your doubts regarding the manufacturer of this product.

It is a product for those individuals who are passionate about aquarium tanks. Regulating the CO2 flow inside the tank without experiencing any alteration in the flow of pressure, it consists of a regulator with a dual pressure gauge. It lets you know the output pressure that goes inside the tank and the actual pressure inside the cylinder.

The best thing is to have 200g of citric acid, 200g of baking soda, and 300g of water to make your carbon dioxide. In contrast, other cylinders need to be filled with gas. ZRDR's cylinder has a pressure valve that monitors the pressure; the moment it goes beyond 30kg inside the cylinder, it automatically releases the excess gas and brings the pressure back to normal.

The package includes an air volume trimmer valve, which you can tweak according to your need, plus a 12v solenoid valve that can automatically turn on and off because of its 24h timer option. This lets you be in complete control of your usage of CO2.

And to make your aquarium system more efficient, it comes with a brilliant diffuser. A diffuser breaks bubbles from the bubble counter into a fine spray which helps them dissolve easily into the tank. In addition, ZRDR provides you with the bottle placement base, which gives the cylinder much-needed stability and safety.

The timer of the solenoid valve is of low quality, which may be the cause of its malfunction.

Why We Love It

  • The manufacturer used stainless steel to make this system.
  • Bottle placement base for stability.
  • Dual pressure gauge.

What You Should Know

  • It may lack the quality of its solenoid valve.

2. FZone Aquarium CO2 System

This product from FZone is light and easy to install. The outer structure of the regulator is made up of tough aluminum alloy. Other parts, like needle valves, are copper electroplated, and the pressure gauge is stainless steel. Using these solid materials, make sure that it works for long periods without getting rusted.

Assembling and setting up this device for your aquarium tank becomes easy, as it comes with all materials and tools to get you started with your system. In addition, it accommodates good anti-leaking seals that save you from harmful gasses.

However, it does not consist of a diffuser and drop checker, making CO2 harder to dissolve in the water, which slightly drops the efficiency of this aquarium kit. Also, you must get a separate cylinder because it does not have one.

But it has a high-quality dual-stage gauge that makes up for its deficiency. The Dual gauge pressure allows you to pump gas consistently and constantly, irrespective of the pressure inside or outside the fish tank. In addition, the pressure gauge gives you the reading of the cylinder and helps you obtain precise control of the CO2 pressure inside the cylinder.

The other thing that makes up for its efficiency is its solenoid valve. The significant part is that it is a 12v DC solenoid valve, simultaneously making it stable and safe. In addition, it has a 24h timer that can operate automatically according to your settings. Apart from all this, it is one of the quietest systems on the market.

This kit has a bubble counter with a check valve to block any liquid from flowing back toward the solenoid valve. Overall, if you look at this device, it is suitable for a small or medium size planted tank.

Why We Love It

  • The manufacturer used Aluminum alloy and copper to provide durability.
  • 12V DC solenoid valve.
  • Dual pressure gauge.

What You Should Know

  • It does not consist of a diffuser.

3. FZone Aquarium CO2 Generator System

This CO2 generator system is mainly made of stainless steel and uses very little plastic. As a result, it is durable and reliable. Even the cylinder with this device is made of stainless steel, ensuring extra security.

With this package, you don't have to buy anything separately. Every component is included in the aquarium kit. All you have to do is assemble it. Next, you need to purchase the reactants: baking soda, citric acid, and water (you can use any water, you don't need to buy it). That's about it. Making CO2 by yourself saves you extra cash by avoiding gas refill stations.

This one comes with an electrically powered solenoid valve with a timer, allowing you to specify when you want the CO2 injection on and what length of time. But there is a model that comes without a solenoid valve as well.

A check valve accompanies the bubble counter to prevent water from coming back. Due to the bubble counter, you can figure out the proportion of CO2 you are pushing inside the tank and adjust the flow accordingly. Lastly, it has a great diffuser that breaks the bubbles into tiny bubbles. It helps carbon dioxide dissolve in the water. Allows marine life to thrive while wasting minimal CO2.

Why We Love It

  • Release the pressure valve mechanism for the excessive gas inside the cylinder.
  • Solenoid valve with a timer.
  • Accompanied by bubble counter with check valve built in.

What You Should Know

  • It is a single-pressure gauge system.

4. Vivosun Aquarium CO2 System

To ensure your aquarium plants get enough CO2, you will want to install a durable CO2 emitter system for your tank. Brass provides ultimate durability, so why not use it? Barring the regulator knobs and rubber washers to avoid leaks, this CO2 regulator is made of brass. You will notice this product's solidity and reliability as soon as you hold it.

It has a rather interesting design since the flow meter was installed rather than another pressure gauge. But the principle is the same as what the dual gauge regulator pressure mechanism does. The flow meter tells you the flow rate at which CO2 enters the aquarium tank. The only pressure gauge of this device informs you of the pressure inside the cylinder.

You need to know that this CO2 emitter does not have a diffuser, which makes this product slightly inefficient among the rest of the others. It does not have a bubble counter which helps know your bubble count, and there is no point in having a check valve if there is no bubble counter.

What gives this product a big plus is its state-of-the-art solenoid valve. The solenoid has an attached timer that can be set according to your needs. The solenoid valve outlet has a precise nozzle, and even the nozzle is brass.

This device is different from others because it can easily fine-tune the gas flow via its regulator. Plus, connecting this system to your tank and using it is very simple and safe.

Why We Love It

  • Made of brass to provide reliability and durability.
  • It has a flow meter that tells you at which rate Co2 is entering the fish tank.

What You Should Know

  • It lacks a diffuser.
  • Nor does it have a bubble counter.

5. MagTool Aquarium CO2 System

This CO2 regulator from MagTool is for those who are keenly interested in their planted aquariums. The whole structure of this mechanism is built with copper. The use of copper gives the product good anti-rust characteristics that make it reliable and durable.

The unique selling point of this dual-stage regulator is that it consists of two bubble counters. Both the bubble counters are independent by having their needle valve for adjusting. It depends upon how to use it; you can use both for a single tank or pump gas to two planted tanks simultaneously. Because of this, you could save so much money by not having to buy a whole new CO2 kit for your other fish tank.

This carbon dioxide system has a dual-stage pressure gauge that lets you supply a consistent amount of gas without experiencing any fluctuation from the fish tank pressure. Both pressure gauges allow you to set the flow of CO2 at a perfect level and maintain a balance between oxygen and carbon dioxide inside the tank. In addition, to provide safety, it has a safety valve option that is programmed to automatically open and release the pressure from the cylinder whenever it exceeds.

This product doesn't have a diffuser, so the bubbles it creates are relatively large. It makes bubbles difficult to dissolve inside the tank. You have to buy the cylinder, as it does not have its CO2 cylinder.

It has a 12v DC solenoid valve instead of an AC to improve the system's efficiency. Because of the DC solenoid regulator valve, it operates quietly, uses a lot less electricity to work, and doesn't get heated.

Why We Love It

  • It is made of copper, which gives anti-rusting characteristics.
  • It has two bubble counters.
  • It has a dual-stage pressure gauge.
  • 12V DC solenoid valve.

What You Should Know

  • It does not have a diffuser.

What to Consider Before Purchasing Any Aquarium CO2 System

Carbon Dioxide Cylinder Size

The size of the CO2 bottles depends on the size of your aquarium. Plus, it would be best to be very careful while connecting the cylinder to the system since you can't see carbon dioxide in the atmosphere because of its tasteless, odorless, and colorless characteristics. Carbon dioxide is heavier than oxygen, and any leakages in concealed or less ventilated spaces would replace oxygen with CO2 in the atmosphere. It could take your life without you being aware of it. But that doesn't mean you should not have a CO2 system. Only a little caution is required from you when installing it.


The regulator of the CO2 system lets you adjust the flow of carbon dioxide inside your fish tank. For a healthy aquarium tank, you need to have the correct pressure of CO2. The slightest error in the regulator can lead to mismanagement of pressure, negatively impacting it. There are two ways you can find an imbalance. Either your tank lacks the amount of CO2 that can kill aquatic plants, or the presence of CO2 is more than sufficient in your tank. It makes fish's survival harder and allows algae to grow.

Before setting your regulator, you need to consider several factors to get the accurate flow of carbon dioxide. Often, people think the size of your aquarium matters only when regulating your CO2, but there is much more than that. Like, it depends a lot on what aquatic plant species you have. Also, types of fish are in a tank. Finally, how much the tank has access to artificial or natural light.


The diffuser is attached to the tubing and linked to a bubble counter. The bubbles coming from the tube are large, which is considered bad practice, especially if you have a small or medium-sized fish tank. We use a CO2 diffuser to fragment the large bubbles into tiny ones to solve this issue. If you ask why it is vital to have smaller bubbles than big ones, it is because CO2 dissolves and spreads in the tank.

Second, it makes the system efficient. You get the maximum amount of carbon. Hence, you are required to pump less CO2 into the aquarium. Thus, a diffuser plays a pivotal role in the CO2 aquarium system.

Solenoid Valve and Bubble Counter

A bubble counter is necessary because it is easy to know how much carbon dioxide has been pumped so far inside the tank. By this, you can control the flow of CO2 by adjusting the regulator of the CO2 aquarium system. To be more precise with the flow of CO2, you can get it by complimenting the bubble counter with a solenoid valve.

The solenoid valve is an electrical way to cut off the gas supply or turn on the supply, just like the dam gates do on rivers. It comes with the 24h timer, and you can set it according to your needs, saving you from wasting carbon dioxide, especially during non-photosynthesis. Without a solenoid valve, you are required to do it manually, and each time you turn on the supply, you have to readjust your regulator. Lastly, having no automatic timer limits you from going on week-long vacations, or you need to rely on somebody who keeps them in check the tank in your absence.

Frequently Asked Questions

A lot of people are curious about aquarium CO2 systems, but they're not sure where to start or what to ask.

We've compiled a list of the most frequently asked questions about aquarium CO2 systems so you can find the answers you need without having to search all over the internet.

Which is better inline CO2 diffuser or a CO2 reactor?

It depends on the needs of the aquarium. Inline CO2 diffusers are great for smaller aquariums because they are easy to install, require minimal maintenance, and provide reliable carbon dioxide delivery. For larger aquariums, a CO2 reactor is usually better. The huge advantage of a CO2 reactor is that it does not require much maintenance if any at all. This allows for a more efficient distribution of carbon dioxide throughout the tank. With inline diffusers, there can be pockets in the tank with insufficient carbon dioxide. Still, with a CO2 reactor, this rarely occurs due to its improved distribution system. Additionally, with a CO2 reactor, it's easier to control and adjust the level of carbon dioxide in your tank than an inline diffuser with limited settings and requires more manual adjustments. On top of that, since reactors have no moving parts, they are also more durable than diffusers which may suffer from wear and tear over time and eventually break down.

Nevertheless, the type of filter you use is an important factor when choosing between these two options. Some filters simply don't work well with certain types of diffusers or reactors, so it's important to make sure your filter is compatible before making your choice.

What is the best way to diffuse CO2 in an aquarium?

The best way to diffuse CO2 in an aquarium is by using a CO2 reactor. A CO2 reactor releases the CO2 into the water stream, usually through a diffuser, where it is dispersed throughout the aquarium. It helps dissolve the CO2 much faster and more efficiently than other diffusers, such as a filter. Another benefit of using a CO2 reactor is that it can also help remove excess organic matter, such as detritus and organic waste, from the tank. This increases water quality and helps with plant growth and health.

How do I choose a co2 diffuser?

The first factor to consider is the size of your aquarium or hydroponic garden. If you have a large tank or system, then you should opt for a larger diffuser. The second factor to consider is how much-dissolved CO2 is already present in your aquarium or hydroponic system. If the level is already very high, adding more might harm plants and fish. Finally, it's also important to consider how many bubbles per second (BPS) your diffuser produces. Higher BPS means greater efficiency when dissolving CO2 into the water; however, too much can stress out both plants and fish due to sudden changes in pH levels or oxygen levels caused by too many bubbles at once!

How can I add CO2 to my tank cheaply?

Adding carbon dioxide (CO2) to your aquarium tank is important in creating a healthy and thriving ecosystem. CO2 is essential for the growth and health of many plants and aquatic organisms, so it's important to ensure that your tank has enough. One of the most affordable ways to add CO2 to your tank is through the use of DIY methods. You can use supplies such as bottles, yeast, sugar, and water to create a simple CO2 generator that will slowly release CO2 into your tank over time. Additionally, you can purchase inexpensive pressurized systems that are very easy to install in tanks that provide consistent levels of CO2 over time. Another great way to cheaply add CO2 to your tank is through liquid drops or tablets designed specifically for this purpose. These products contain concentrated amounts of carbon dioxide, which can be added directly into the tank; they dissolve quickly in water and help maintain optimal levels of dissolved gasses in the aquarium. Finally, consider adding live plants into your aquarium - these plants need CO2 for photosynthesis, so they will both naturally add more CO2 as well as help oxygenate the water in your tank!

What PSI should my aquarium be CO2?

The ideal PSI for an aquarium that is running CO2 should be between 20-30 PSI. This is the optimal range to ensure enough CO2 is being delivered to the aquarium while protecting your aquarium inhabitants from any potential harm due to extended exposure to the gas. To further ensure results, we recommend testing for levels of dissolved CO2 in the tank water to measure how much gas is actually making it into the tank. Additionally, depending on factors like temperature, pH, and other variables present in the tank environment, you may need to adjust your target PSI level accordingly.

What Option of Aquarium CO2 System is Best for You?

All the options we presented can be great for you and your home. Now it comes down to personal preference. Remember, what works for one consumer, may only work for some.

We hope this article has given some clarity on what aquarium CO2 systems you want in your home.

Thanks for reading!

Items reviewed:

1. ZRDR Aquarium CO2 System

2. FZone Aquarium CO2 System

3. FZone Aquarium CO2 Generator System

4. Vivosun Aquarium CO2 System

5. MagTool Aquarium CO2 System

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