Last Updated on April 24, 2023 by Coral Realm

Plant life requires carbon dioxide to survive. The plants in your aquarium will take in CO2 from the water and release oxygen. This is why having a planted tank is so beneficial to the health of your aquarium fish.

To maintain the health of the plants in your fish tank you need to ensure they have sufficient CO2 levels to grow and flourish. Both rooted and floating aquarium plants can benefit from a good CO2 regulator in your tank.

Having good quality aquarium CO2 regulators ensures that there is enough carbon dioxide to sustain your plant life, but doesn’t allow excessive levels which promote algal growth and can be very damaging, even killing, your fish.

To allow the CO2 concentration to be even throughout your tank consider getting an aquarium powerhead or aquarium wave maker, which will create water movement in the tank and prevent a build up of carbon dioxide in one area. Air stones can also have this effect in smaller tanks.


8 Best Aquarium CO2 Regulators

Why Should You Use Aquarium CO2 Regulators?

Beneficial to Plant Life

aquarium CO2 regulators

As stated already, plant life inhales carbon dioxide and exhales oxygen. Fish require well oxygenated water to flourish and stay healthy, so the benefits to your tank of having healthy plants are numerous.

If the CO2 levels in your tank run too low, the plant life will be adversely affected.

Low CO2 levels can cause stunted growth, pale leaves and stems, and eventually prolonged low CO2 levels may cause the plant to die.

Installing aquarium CO2 regulators will ensure that the perfect level of CO2 in your tank is maintained, giving your plant life the perfect conditions to thrive.

Beneficial to Fish

Animals breathe in oxygen and breathe out carbon dioxide, so your aquarium life are constantly adding more CO2 into the water. If this builds to an extreme level it can start to suffocate the fish, and affect the pH balance of the water.

Having a CO2 regulator system installed will help you monitor the carbon dioxide levels so you can take action if needed. This will help your nano saltwater fish or your freshwater aquarium fish to thrive.

Fighting Algal Growth

Algae is a major threat to the health of your fish and aquarium. Having a build up of algal growth can cause ammonia levels to rise and can lead to infection and disease in your fish and plant life.

High carbon dioxide levels greatly inflate the rate of algal growth. Algae is essentially just a colony of very small plants, and as we’ve said plants breathe in CO2. So you might think having a high CO2 concentration in your tank will be good for the plants, which they are, but it means algae will proliferate too which will be terrible for the fish.

Therefore, it is a very fine line between having too high or too little a concentration of CO2 in your tank. This is where having good quality aquarium CO2 regulators is important. It keeps the balance and lets you know what is going on in your tank.

Always by these systems from reputable sellers, like these CO2 regulators we will review below.

8 Best Aquarium CO2 Regulators Reviews

8 Best Aquarium CO2 Regulators

1) DoubleSun Solenoid Aquarium CO2 Regulators with Dual Gauge Display and Bubble Counter 

DoubleSun Solenoid Aquarium CO2 Regulators with Dual Gauge Display and Bubble Counter
  • UPGRADED SOLENOID VALVE- Newest the upgraded solenoid product is more stable to the output airflow and added safety and reliability. Low power...
  • MINI DUAL GAUGE DISPLAY- Mini dual gauge display with clear tick marks and numbers allows you clearly and accurately read the pressure(0-2000 psi) in...
  • HIGH PRECISION STRUCTURE-This is a great aquarium regulator. The bubble counter has a built-in check valve function on the regulator is adjustable by...
  • STRONG COMPATIBILITY-The CO2 aquarium regulator is compatible with most brands of high density tubing to inject your aquarium with CO2 quickly and...
  • WHAT’S IN YOUR PACKAGE?- 1 x dual gauge regulator; 1 x wrench; 1 x hex wrench; 1 x extra seal ring. You can get it set perfect for a planted...

DoubleSun is a company with a very good reputation. So, you can be assured that this aquarium CO2 regulator is manufactured with high-quality parts that are going to last. It is quite generalized and is compatible with most high density tubing and a range of carbon dioxide diffusers and atomizers.

The dual display is clear and easy to read, and you can configure the regulator to release precise amounts of carbon dioxide over a large range. The dual gauge design allows you to read the pressure accurately. The low-pressure gauge measures the output pressure and the high-pressure gauge shows the pressure of the cylinder and remaining CO2. The micro adjustable valve allows for fine tuning of the pressure released. This ranges from 150 to 250 PSI. The solenoid valve functions very quietly and at a low temperature to minimize disturbance to your aquarium.

This regulator includes most of what you need for set-up; it comes with a tighten tool, a hex wrench, an extra seal ring and a detailed instruction for use. It doesn’t include the tube and carbon dioxide tank.

The DoubleSun Solenoid Aquarium CO2 Regulator is a reliable regulator that will continue to perform reliably for a ling time. The instructions, however, are fairly difficult to understand. An extra stand is required if you need the CO2 regulator in a different position, as the bubble counter doesn’t rotate.

2) Fzone Triple Stage Aquarium CO2 Regulator with DC Solenoid and Bubble Counter

This aquarium CO2 regulator by Fzone is made of a hard aluminium alloy, and the surface is spray treated. This means that you won’t have this product break on you; it is very durable.

It has a triple stage decompression design, and the outgoing pressure knob and fine tuning are easy to adjust, allowing for a very stable output pressure and CO2 flowrate. The triple stage decompression means you won’t get the end of tank dump effect, where lots of CO2 is “dumped” into your tank, which can be very harmful to your fish. The working pressure can be adjusted from 0-60 PSI.

A 12V DC solenoid valve is utilized which is a safer and more stable option then the AC valve some products have. It uses less power and makes almost no noise. You can automatically turn the CO2 output with a timer, which is very useful as you do not need to use CO2 at night, as the plants only use it to grow during the day.  

This regulator is compatible with 5/8″ UNF threaded disposable CO2 cartridges, Paintball tank and CGA320 threaded cylinders. It can be used for both top open and side open tanks. The bubble counter and all tools you need for installation are included. You can read the flow rate directly via the bubble counter, and it also stops water backflow to the bottle.

3) Vivosun Aquarium CO2 Regulator Emitter System with Solenoid Valve Flowmeter

Vivosun Aquarium CO2 Regulator Emitter System with Solenoid Valve Flowmeter
  • Durable Material: Long-lasting durable brass components will function for many years without rusting
  • Specifications: 1.58" high pressure gauge: 0-4000 PSI; Flowmeter: 0-15 SCFH; Inlet connection: cga-320
  • Application: Perfect for enhancing the amount of available carbon dioxide and accelerating plant growth rates and yields by up to 40% in indoor hydroponics, grow rooms, grow tents and warm houses
  • Components: A precision regulator, flow gauge, and industrial solenoid valve, 5 meters free plastic dispensing tubing and USA standard 3-prong plug (hose tail to suit 4.2 mm hose diameter)
  • Multiple Options: This CO2 regulator will allow you to maintain ideal CO2 levels for optimal growth

Vivosun has a brilliant reputation for making well-priced, durable, well-constructed products. They are more well-known for making hydroponic grow tents, but this CO2 regulator can be used in an aquarium too.

Similarly to the other manufacturer’s models, the Vivosun Aquarium CO2 Regulators Emitter System is also made with metal and has an electric solenoid valve. The solenoid valve allows for the attachment of a timer.

The 1.58″ high pressure gauge measures from 0-4000 PSI. The inlet connection is a standard cga-320. The flowmeter ranges from 0-15 scfh, so it should fit all of your needs.

As this is a single gauge CO2 regulator, you won’t quite get the same control over the flow of CO2. Some reviews say that after a few months of use the flow rate becomes irregular, but many more are perfectly happy for months and months. Some users also say that it makes quite a loud humming noise whilst in use.

4) Sylphid Dual Gauge Display Aquarium CO2 Regulators with Check Valve 

This aquarium CO2 regulator by Sylphid is a very high-quality durable product. This CO2 regulator is specifically designed with planted aquariums in mind, so you can be sure that your plants will be looking their best.

This is a dual-stage system, with a solenoid valve so you can fit a timer, and a bubble counter with check valve function which stops water backflow to the CO2 canister. You don’t need tools to install this regulator which makes setup very easy.

You can accurately fine-tune the amount of CO2 released, which is very useful in aquariums as a large influx of carbon dioxide will disrupt the pH of the water and the chemical balance and cause your fish major distress.

With professional sealing technology you don’t need to worry about any carbon dioxide leaks in this aquarium CO2 regulator, and the high corrosion resistant materials make it very durable. 

5) Aquarium CO2 Regulators by Titan Controls

Titan Controls CO₂ Regulator - Compatible with Titan Controls CO₂ Controllers and Other CO₂ Controllers, For Gardens
  • Compatible with Titan Controls CO2 Controller or other 120 volt controllers and timers
  • Precision accuracy flow meter - 0. 5 to 15 SCF/hour
  • Features heavy-duty solenoid valve
  • High quality oil-less pressure gauge
  • Includes two plastic tank washers and 12 ft of CO2 dispensing line

Featuring a brass construction for long-lasting dependability and durability, this aquarium CO2 regulator by Titan Controls is sturdy and will last the distance.

It features a heavy duty solenoid valve, and is fully compatible with other Titan Controls CO2 Controllers, or other 120 volt controllers and timers. It has a precision flow meter which accurately measures CO2 flow rate from 0.5 to 15 SCF/hour.

A high-quality no oil pressure gauge enables quick and accurate reading of the pressure from the tank and outflow. This product includes two plastic tank washers, and 12 feet of dispensing line, so you will definitely be able to reach your aquarium!

6) Fzone Pro Series Dual Stage Aquarium CO2 Regulator

Fzone Pro Series Dual Stage Aquarium CO2 Regulator
  • Dual stage construction & adjustable output pressure. Dual stage construction provides stable output pressure regardless of how much CO2 gas remains...
  • Modular manifold block design. Two manifold blocks are included. Each block comes with its own high-precision needle valve and can be operated...
  • Safety and precision in mind. Our regulator has a built-in safety valve. It will open automatically to release the pressure when it exceeds 100 PSI....
  • Solenoid runs on 12V DC instead of conventional 120V AC. This regulator adapts to 12V DC, which is more stable and consumes less power. The solenoid...
  • Attention. Suitable for North American CO2 cylinder with CGA320 adapter! Installation tools are included.

The Fzone Pro Series Dual Stage Aquarium CO2 Regulator is the second from this company on our list of best aquarium CO2 regulators. They are well known to produce high quality and durable products.

The dual stage regulator controls the pressure and maintains a stable CO2 output. This eliminates the sudden CO2 dump which can happen due to the decrease in pressure towards the end of a CO2 tank, called end-of-tank-dump catastrophe.

With a solenoid valve, a bubble counter, and a needle valve, you will have full control over the timing and amount of carbon dioxide injected into your aquarium. 

It has a unique modular manifold block design. Two manifold blocks are included, and each has a high precision needle valve and bubble counter. They can be operated independently for use in multiple aquariums, which can be incredibly useful. 

The needle valve allows you to fine tune and precisely make minor adjustments to the outflow of CO2, so you can perfect the environment you want to create.

The mini dual display allows for easy reading of the PSI and CO2 settings so you can confirm that they are always in the levels you require. The tools required for installation are included so the setup is kept as simple as possible.

7) Aquatek CO2 Regulator with Integrated Cool Touch Solenoid

Premium AQUATEK CO2 Regulator with Integrated Cool Touch Solenoid
  • Cool-touch, industrial solenoid design; Brass constructions for long-lasting durability and dependability
  • Precision needle valve for fine tuning release of CO2; Precision output working pressure adjustment knob: 140 PSI Max
  • Includes bubble counter with integrated check valve
  • Compatible with most high density tubing
  • Compatible with most CO2 atomizer and diffuser

This Aquatek aquarium CO2 regulator has a brass construction for long-lasting durability and dependability. It will be guaranteed to last a long while for your tank.

The solenoid valve has a cool-touch designed, which means it will not get overheated and cause issues like other valves you might find. The precision needle valve is used for fine tuning the release of carbon dioxide into your aquarium. The precision output working pressure adjustment knob gives a maximum outflow pressure of 140 PSI

It is fully compatible with most high density tubing, CO2 atomizers and diffusers. It comes with its own bubble counter with integrated check valve, which prevents backflow of water into the system.

8) S.T. International 2-Gauge Aquarium CO2 Regulator

S.T. International Aquarium 2-Gauge Professional CO2 Regulator, Silver
  • Designed with an easy to adjust decompression pressure gauge to provide stable and accurate CO2 output
  • The CO2 Regulator can be used with disposable cartridges
  • Has a patented solenoid magnetic valve
  • Highly effective and energy efficient
  • Operates quietly and does not produce heat and designed for long term use

This aquarium CO2 regulator by S.T. International provides a steady stream of carbon dioxide into your aquarium courtesy of an easy to adjust decompression pressure gauge to provide stable and accurate CO2 output.

The regulator can be used with reusable and one-use disposable cartridges. It has a solenoid valve, which is very effective and efficient, and as such operates without making loud noise or producing excessive heat.

Armed with universal voltage, both 220 and 110V, which allows for worldwide use which is very useful if you live elsewhere. It has been granted accreditation with both PSE and CE which guarantees safety. It is very durable and made for long term use.

The washers used are an unusual size however, and may be hard to find if they need replacing. There is also no power light, which can be a little annoying as you have to check closely.

How Do You Know Which Of These Aquarium CO2 Regulators is Best?

There are a number of ways to see if a regulator is the right fit for you and your aquarium. Let’s go through some of the chief points you want to keep an eye out for when shopping around.

How To Choose An Aquarium CO2 Regulator


You want the best aquarium CO2 regulators to be as simple as possible whilst maintaining all its functionality. You also want it to last, so we like to ensure our regulators are made with stainless steel or brass.

An important function you may want on your regulator is a fine-tuning knob. This allows you to make small adjustments to the flow of CO2 into the tank, which can be extremely useful.

You can check how your aquarium plants and life is doing over the course of a few days and then you can make minor adjustments based on your observations.

Some gauges are particularly small, so readability comes into play as well, as you do actually want to be able to see at a glance what the pressure is like!

Decompression Stages

How the carbon dioxide in the tank is depressurized before being imputed into the tank is quite an important factor. There are primarily two different options on the market; single or dual stage regulators.

A single stage regulator will take the pressurized CO2 from the tank, decompress it and pump it directly into the tank. A dual-stage regulator has an extra step, and will take this decompressed CO2 from the first stage and allow for finer adjustments. There is also a triple stage option by Fzone which allows for even greater control.

Double-stage CO2 regulators are generally more expensive than their single stage counterparts, and whilst the extra control over flow rate is very useful, there aren’t many complaints about single-stage regs. It can however be fairly difficult to obtain and maintain a steady flow rate.

It depends on your aquarium and your personal choice. We suggest if you have an advanced aquarium then get a double or triple-stage.


You do need to make sure the regulator you buy will fit the carbon dioxide tank you have. It would be extremely frustrating if not! You can purchase CO2 regulators which are compatible with multiple variations of CO2 tank.

Refillable paintball cylinder tanks are fairly common, as are one use tanks. See what tanks you will be using and then check the regulator you buy will fit.


Whilst the most basic of regulators will still function well and do the job, any additional accessories you can get will give you more control over the flow rate and the general state of your aquarium. These are the most common additions you will see on regulators.

Solenoid Valve

A solenoid valve is an extremely useful addition to the regulator. It will allow you to put the regulator on a timer. This is incredibly useful as you will save CO2 and energy by turning the regulator off during the night when it is not needed in the tank.

While it may not seem like it will have a big impact, imagine if you had to turn your aquarium light off manually every day! It will soon get tiresome, and adding CO2 into the aquarium at night may be harmful to your fish.

Needle Valve

This piece of equipment is very important for having a safe and highest standard CO2 regulator.

Also known as a pressure relief valve, it gives you exact control over the amount of gas that is released into your aquarium. You are able to fine tune and have complete control over the flow rate of CO2.

The needle valve avoids you having any CO2 dumps into your aquarium, which can cause serious damage to your fish.

Check Valve

A check valve is a vitally important safety feature. It will prevent any back flow of water from your aquarium into the regulator system.

When the carbon dioxide begins to run low, water can be drawn up the tubing and into the system. This backflow of water can have significant negative impacts on the functioning of the regulator. A check valve is therefore a very handy bit of equipment.

Bubble Counter

A bubble counter makes it very easy to see what the flow rate of CO2 is into your aquarium. You can visually see the number of bubbles per second of CO2 being inputted, hence the name bubble counter.

A lot of aquarium CO2 regulators don’t come with a bubble counter as standard, but it is very useful in quickly getting the flow rate right. Many bubble counters also help with preventing water backflow as well.


The better aquarium CO2 regulators come with two pressure gauges; high pressure and low pressure.

The high pressure gauge is for seeing the pressure in the CO2 tank, and tells you how much CO2 is remaining. The low pressure gauge tells you the pressure of CO2 into your aquarium, so therefore the basic flow rate. Be aware that a regulator doesn’t have to be a dual-stage regulator to have two gauges.

How to Set Up Your Aquarium CO2 Regulator

Many regulators come with all the tools you will need to install the product.

Follow the manufacturers guidelines and you should be good to go in no time at all. But in general, all you need to do is attach the regulator to the CO2 tank, and equip the tubing and diffuser to the outflow end. Use a strong tape to bind the seals of the regulator.

Put the diffuser in your aquarium; suction pads will help to keep it in place. A CO2 drop checker is very useful for keeping an eye on the CO2 levels in your aquarium. The recommended dissolved CO2 level for a planted aquarium is roughly 26 to 35 PPM. So if yours is a little under or over your can adjust the regulator as needed.


To maintain vibrant plant life in your aquarium you should get one of these aquarium CO2 regulators. It will add extra carbon dioxide into your aquarium which the plant life will use to grow and stay healthy.

Out of all the aquarium CO2 regulators above, the only triple-stage model is the product by Fzone, which will offer greater safety for your aquarium than other models. However it does depend on your price range and the type of aquarium you have. Any of the models are great choices, but the best CO2 regulators are the Fzone Pro Series Dual Stage Aquarium CO2 Regulator and the S.T. International 2-Gauge Aquarium CO2 Regulator

S.T. International 2-Gauge Aquarium CO2 Regulator

These models are on the expensive side though, so good cheaper options are the Vivosun Aquarium CO2 Regulator Emitter System and the Sylphid Dual Gauge Display Aquarium CO2 Regulator

Sylphid Dual Gauge Display Aquarium CO2 Regulator

Have fun buying the best aquarium CO2 regulators for your aquarium! 

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Coral Realm

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