Top 15 Best CO2 Reactors in 2023

Having the best CO2 reactor in the market means there is nothing like witnessing the calm and serene effect of having an aquarium of beautiful, healthy, happy fish in your favorite relaxing place.

As there is a certain calming feeling about owning an aquarium and watching your fish grow and thrive, you must try out these top 15 listed CO2 reactors to enhance this beautiful experience and safeguard your fish, certified to bring out the very best of your aquarium.

Why Do I Need A CO2 Reactor In My Fish Tank?

Buying an aquarium and keeping fishes inside it is something anyone can do. But, keeping them healthy and maintained is another story.

There is a lot more that your fish need besides water and a few decorative pieces. There is more of a fish tank than a bubbling filter and every fish enthusiast is aware of this. Maintaining the perfect fish tank requires a balanced amount of oxygen and carbon dioxide as well.

All types of fishes and aquatic plants need Carbon Dioxide as it is a need for them to thrive and live healthily within the tanks. However, it can be a little difficult to get the right level or the perfect balance of oxygen supply with carbon dioxide.

This is where a CO2 reactor comes in handy! Let us see why they are so important and necessary for good fish and plant health.

What Is A CO2 Reactor And How Does It Impact My Fish?

CO2 reactors are devices that help keep a balance between oxygen and carbon dioxide content in a fish tank, as the surplus of any one component can cause more harm than good. These optimum levels are not only necessary for plant growth but they also keep the fishes healthier and happier.

A fish tank’s only source of CO2 is from the outside air. This makes the amount of naturally occurring CO2 very less as the fish tanks are usually covered by a lid that mostly stops any flow of carbon dioxide from the atmosphere into the tank.

CO2 reactors offer to provide fish tanks with the required levels of carbon dioxide gas. What is even better is that CO2 reactors are completely risk-free. They are extremely safe to use in your tank. They have no effects and are easy to install and make use of.

More importantly, depending on the reactor you use, most reactors have automatic valves. These valves can control the release of carbon dioxide into the water. So, the only impacts that you see are happy fishes! (And a happy you, of course!).

How Does A CO2 Reactor Work?

The main purpose of a reactor is to inject CO2 into the fish tank. A reactor releases CO2 in the water in the form of bubbles, which should ideally dissolve in the water current to distribute the necessary nutrients to the plants and fishes in your tank.

CO2 reactors are the most preferred method of CO2 supply, recommended by many pro users.

Now this brings me to a comparative analysis of which are the best reactors available in the market.

Best CO2 Reactor Comparison Chart 2023

As there are many CO2 reactors available in the market, it is important to know what type would suit your fish tank better. The table below highlights and sums-up all the requirements to look for when buying a CO2 reactor.

Which Are The Best CO2 Reactors To Buy?

After plenty of research, I have come up with a list of 15 best suggested CO2 reactors. You can consult this list if you are having difficulty in making a decision.

• Best Overall – Gulfstream Tropical AGU00528 CO2 Reactor
  “Built in a compact and easy to handle design,very light weight, provides complete CO2 dissolution, most efficient and very affordable.”
• Best Budget – Driak Aquarium Fish Tank CO2 Reactor
  “Being eco-friendly and made from top quality material, this aluminum reactor is very light weight, enabling easy handling and fitting of it in the tank. Best productivity in affordable budget.”
• Best Inline – Aquatics InLine CO2 Reactor
  “The perfect choice for ease of installation and cleaning, efficiently protects the build-up of algae in the tanks.”
• Best External – ISTA I539 CO2 Reactor
  “Best for CO2 production that absorbs well and gives out no bubbles. It is easy to assemble with good how-to instructions.”
• Best for Plants – Gulfstream AGU-00529 CO2 Reactor
  “This best way to fully diffuse the CO2 into the planted tanks. It offers 100% distribution of the CO2, encouraging plant growth.”
• Best for Nano – IDS Aquarium Super Atomic CO2 Reactor and Atomizer
  “With a strong refining efficiency, the IDS Super Atomic completely dissolves carbon dioxide in the cylinder and takes the water supply and allows it to photosynthesize – carrying out two actions in one small package.”
• Best ISTA Turbo – ISTA Turbo External CO2 Reactor
  “The patented impeller design completely crushes the CO2 bubbles and with its compact size, you can even use it externally.”
• Best Professional Kit – Wuyouchy SUS304 Stainless Steel CO2 Reactor
  “A more professional, reliable, efficient generator to keep your plants growing better than ever before. It produces high, pure CO2 based on acid-alkali reaction theory. It is also highly durable.”
• Best Sera Flore Active – Sera Flore Active 1000 CO2 Reactor
  “It is the best high performance CO2 reactor for complete dissolution of CO2 in the brand range. You can install it internally or externally by simply mounting it to your water pump.”
• Best for Small Aquarium – Vivona Mini CO2 Reactor
  “Most light weight reactor that produce a good supply of CO2, a perfect fit for small sized tank,very easy to install and handle.”
• Best Hang-on Back – Bubble Magus MF70 CO2 Reactor
  “The Bubble Magnus reactor offers a pollution, algae free tank environment due to its filters. It’s up-flow design makes the CO2 rotation, perfect.”
• Best Aqua Medic – Aqua Medic HR400 CO2 Reactor
  “This acid neutralization reactor from Aqua Medic is by far their best. It is light weight, has a glass body that is strong and durable for a long term use. A bit pricey as compared to other.”
• Best with Canister Filter – NilocG Aquatics Inline CO2 Reactor
  “This easy to use, discreet CO2 reactor provides professional quality and value. It mounts inline with canister filters of an inner diameter of 12mm (1/2”) and outer diameter of 16mm (5/8”).”
• Best for Planted Aquarium – JIAWANSHUN 1X4L Aquarium CO2 Reactor
  “A complete generator reactor system with maximum productivity and amazing functionality. It offers complete dissolution of CO2 offering complete control on time and pressure.”
• Best for Aquariums – TAAM Rio 90 CO2 Reactor
  “Comprising of the surface skimmers that are dual, this device prevents clogging. The filter pads and skimmers are one of its highlighted features. Keep your tanks debris free with this reactor.”

Reviews Of The Best CO2 Reactors in 2023

There are several CO2 reactors on the market. It can become stressful trying to find the right one for you. Especially, because each of them holds a particular feature that fits to a certain tank needs and might not be ideal for another.

Save your time of searching the entire web for solutions and check out this concise list of the top best CO2 reactors available online. Go through my list, provided with a concise research on product pros and cons for every CO2 reactor to choose the one that you think fits your needs the most!

1. Best Overall: Gulfstream Tropical AGU00528 CO2 Reactor

The Gulfstream-Tropical reactor is compact, easy to install and simple to operate. It is cost-effective and popular because of its high quality. Installing the Gulfstream-Tropical reactor is very convenient; any beginner can also do this by simply connecting it with the canister.

This CO2 reactor automatically distributes CO2 equally in all parts of the tank and even gets rid of CO2 bubbles, which is a regular issue that fish tank owners have to face, while fixing reactors into their tanks.

This reactor is the perfect device for owners of small tanks. Its mechanism can work with 200 plus gallons of water every hour. This processing time is perfect for any typical fish owner.

Key Features:

• Impeller design that is patent
• ‘Max-Mix’ Reactor
• User-friendly
• Very Affordable

Product Specifications:

Dimensions	3 x 1.6 x 6.5 inches
Weight	294 grams
Weight of boxed product	340 grams
Capacity	For an aquarium of over 80 liters

2. Best Budget: Driak Aquarium Fish Tank CO2 Reactor

This is a CO2 reactor that is eco-friendly and made from top quality material. The silver reactor is very light weight, enabling easy handling and fitting of it in the tank.

The bubbles are fine and keep the environment clear of any misty distortion. The body of this reactor is treated with nickel-oxide. The knurling design over it makes it slip-free in wet handling.

Being the best budget product in the reactor market, Draik beats all the odds by producing 100% results, keeping the tank sparkly and adding an elegant feel to it, due to its silver body. The suction cup provided in the kit makes it easy to setup.

Key Features:

• Best priced
• Easy to install
• Energy Saving

Product Specifications:

Dimensions	6 cm (length) x 24mm (diameter)
Weight	30 grams
Weight of boxed product	Same
Capacity	Medium/small sized tanks

3. Best Inline: Aquatics InLine CO2 Reactor

This high quality reactor is every fish-tank owner’s dream, literally. It contains all the high-performance features that a reactor should have. The sturdy acrylic body provides top class impact response to avoid breakage, which makes it last for years.

Its installation is easy and can be outside or inside with a bracket.Since this is an in-line reactor, it also guarantees the removal of algae that can harm your aquatic life.

This reactor has exceptional CO2 absorption features. These features are bound to keep your fishes and plants happy. Best installation is with hose of 16 mm, when connecting to filter or pump.

The in-package, a ceramic replacement dish is a plus! This is a good investment for any aquarium owner out there.

Key Features:

• Durable premium quality material
• Wall-mount bracket for easy hanging
• Reduces algae build up

Product Specifications:

Dimensions	12 – 15mm and 16 – 22mm
Weight	54 grams
Weight of boxed product	90 grams
Capacity	1/2 – 5/8 (12 – 16 mm)

4. Best External: ISTA I539 CO2 Reactor

This reactor is famous for being the best one available in any aquatic market as it has the capability to operate with zero sound and an unmatched smoothness!

It only requires a flow rate that is slow which ensures the best long term performance. Although, it produces a slight sound at the time of operation, the sound is quick to go away.

The ISTA I-539 reactor produces an impressive amount of CO2 without the formation of any bubbles. This not only keeps the surface clean and good looking, but also, clear of any disruption of current.

For a reactor that has so many benefits, it is available at a low cost offering a good few years of usage. It comes with a few drawbacks like any other device. These drawbacks include a slight noise as well as the slow-flowing rate. But, if you can look past these minor flaws, then you are good to go!

Key Features:

• Bubble resistant
• Impact sustainability
• Acidic level durability

Product Specifications:

Dimensions	0.1 x 0.1 x 0.1 cm
Weight	9.07 grams
Weight of boxed product	318 grams
Capacity	76-100 liters

5. Best for Plants: Gulfstream AGU-00529 CO2 Reactor

It is a two-in-one reactor. Its installation can be both external and internal. The external reaction allows for more space in the aquarium. This can be of great help to those with smaller tanks. It’s assembly and installation is very easy and takes only a few minutes.

Cleaning it is super easy as well. This reactor can last and serve for several years. It is durable enough to easily put up with any sort of impact. The perfect choice for you I you are a newbie in fish tanks set up.

Considering all the amazing features, this reactor comes at a very low price.

Key Features:

• Can resist acidity
• Capability to resist external impact
• Easy maintenance

Product Specifications:

Dimensions	6.4 x 5.3 x 5.1 cm
Weight	294 grams
Weight of boxed product	294 grams
Capacity	600-1000 liter per hour

6. Best for Nano: IDS Aquarium Super Atomic CO2 Reactor and Atomizer

The IDS Super Atomic has the unique property of being both a reactor and an atomizer so you can get the best of both worlds. And with its simple, compact size, it works great for anyone with a nano tank.

It has an affordable price, is easy to dismantle and thus easy to clean and has a very simple installation process.

It isn’t as durable as its counterparts, and may only last between six months to over a year – but with the very low price, you can easily replace it when the time comes and won’t even feel a hit on your wallet.

Key Features:

• Lock-nut tooth design ensures no leakages
• Completely dissolves the CO2
• Ceramic discs included

Product Specifications:

Dimensions	1.7 x 1.2 x 0.5 inches
Weight	18 grams
Weight of boxed product	18 grams
Capacity	Less than 20 gallons

7. Best ISTA Turbo: ISTA Turbo External CO2 Reactor

If you are finding it difficult to decide between a diffuser or a reactor, then get this 2 in 1 device instead! The ISTA reactor-diffuser will meet all your requirements. It will ensure adequate supplies of CO2 to your tank. It is leak-free and easily attachable.

After easy assembling, you can begin using it by a simple attachment to the canister. What sets it apart from other reactors is its ability to provide the best even with an expensive price tag.

It requires a little more careful handling because of its fragile built. Without proper handling, it may suffer from irreparable damage. Another drawback is the short-length hose barbs. If you can look past these minor things, then be sure to get this reactor!

Key Features:

• Two-in-one reactor and diffuser
• Best in affordability
• Multi-purpose reactor

Product Specifications:

Dimensions	5 x 7 x 9 inches
Weight	28 grams
Weight of boxed product	28 grams
Capacity	1.6 liters

8. Best Professional Kit: Wuyouchy SUS304 Stainless Steel CO2 Reactor

Wuyouchy is made up of stainless steel and comes with all the necessary attachments and equipment for the easy setup of this reactor. What sets this device apart from all the other ones is its sturdy stainless steel body that enhances its durability.

This professional CO2 reactor consists of safety valves that open and close at the required time. The safety valves control the flow of carbon dioxide into the tank. The operation is manual and can be automated by using the model with solenoid.

It works best for smaller tanks and can build proper pressure as required in them as compared to the larger tanks. The process of assembling this reactor is easy; however, the connector tube is of a smaller length and to be managed likewise.

Key Features:

• Stainless steel body
• Safety valves

Product Specifications:

Dimensions	13.5″ H x 4.5″ W x 3″ D
Weight	422 grams
Weight of boxed product	422 grams
Capacity	Over 160 gallons

9. Best Sera Flore Active: Sera Flore Active 1000 CO2 Reactor

If you are someone who is looking for a bigger reactor with more powerful working, than the Sera-Flore 1000 is the perfect choice! It is of a bigger build and ensures a proper supply of carbon dioxide throughout the entire tank.

Because of its larger size, it comes at a more costly price. It offers a motor built-in and can process 160 plus gallons of water.

The reactor comes with easy-to-follow instructions. These instructions can make the installation and assembling process much easier. Taking it apart for cleaning and maintenance is easy as well.

When it comes to performance, this reactor never disappoints. It can easily process 500-1000 bubbles every minute. This ensures the production of CO2 in a mist form. This mist ensures equal distribution of CO2 all over the tank.

Key Features:

• It can process 160 gallons of water
• Built-in motor

Product Specifications:

Dimensions	17.1 x 6 x 4.25 inches
Weight	1991 grams
Weight of boxed product	1991 grams
Capacity	10-15 gallons.

10. Best for Small Tanks: Vivona Mini CO2 Reactor

The Vivona Mini is perfect if you’re looking for a small, handy reactor that you can stick onto the side of the tank wall and hide easily with foliage so it looks as if it isn’t even there!

And with its unique thermoplastic ABS material, it’s made of highly durable materials. So if you want to give it a deep, good clean, you don’t need to worry if the water is too hot. And cleaning the Vivona Mini is incredibly easy!

Installing it is even easier. Stick it to the side with the suction cups, hook up the hose and you’re good to go!

Key Features:

• Small size

Product Specifications:

Dimensions	3.5 x 3 x 6.5cm
Weight	86.2 grams
Weight of boxed product	90 grams
Capacity	10 – 20 gallons

11. Best Hang-On Back: Bubble Magus MF70 CO2 Reactor

Another great option for owners with sizeable fish tanks! This reactor is a multi-purpose fluidized kit, offering 100% disbursement of CO2 in the tanks.

It has an up flow design and keeps the tank pollution free. With its use you will not find any algae issues, discoloration of odor in the tanks.

Designed to be extremely durable, this reactor also has aesthetic visuals, especially, when working underwater. It’s also very easy to clean – all you have to do is take off the twist-lock cap and you’re good to go!

Key Features:

• Hang-on back filter
• Pollution Resistant Filters

Product Specifications:

Dimensions	3.1 x 3.1 x 14 inches
Weight	18 grams
Weight of boxed product	20 grams
Capacity	Below 20 gallons

12. Best Aqua Medic: Aqua Medic HR400 CO2 Reactor

This acid neutralization reactor from Aqua Medic is by far their best. Even though it has a simple design, the HR400 doesn’t skimp out on quality which is a surprise for a reactor of its size.

It’s a slightly pricey reactor and it has a slow turnover rate, but the quality and the thinnest bubbles that it produces, makes up for its minor glitches.

The durable glass body is strong enough to bear the water impact and is convenient to use with multiple hose and fittings. If you want a reactor considering a long term investment into product quality, then this is the perfect reactor for you.

Key Features:

• Acid Neutralization reactor
• Small size

Product Specifications:

Dimensions	16/22mm
Weight	96 grams
Weight of boxed product	Variable
Capacity	Almost 20 gallons

13. Best with Canister Filter: NilocG Aquatics Inline CO2 Reactor

This high quality acrylic reactor helps in optimum plant growth. It does so by having a fine mist of CO2 paired with turbulent-mixing. These two functions ensure proper absorption and supply of CO2 in the water.

Its design is compact, providing more room for the fishes to swim around freely. It is built-in with O-ring seals to ensure easy maintenance.Mounting in-line with the canister filters is very easy to do with this product.

This sturdy acrylic reactor is very durable and impact resistant offering 100% diffusion. It is the perfect choice for medium or small sized tanks as it conveniently fits with the canister filter, leaving abundant space in the tank.

Key Features:

• 100% pro plant growth
• Compact design

Product Specifications:

Dimensions	6 x 15 x 6 inches
Weight	> 5 pounds
Weight of boxed product	5 pounds
Capacity	5-12 gallons

14. Best for Planted Aquarium: JIAWANSHUN 1X4L Aquarium CO2 Reactor

This is the most well- equipped reactor of all available products. This is a complete CO2 generator system, supplied with pressure relief valve, solenoid valve, 3 staged filter system, bubble counter, gas cylinder and checking valve too.

This reactor system allows you to have complete control on the CO2 diffusion; thus, ensuring healthy growth of in tank plants and habitat. This is the most recommended for planted aquariums, built to supply to medium and large sized tanks.

The best factor is that the brand offers tutorial videos and a complete comprehensive guide or the installation and use of this system, making it easy to maintain.

This reactor is a costly as compared to the other reactors, but its value is well worth the money.

Key Features:

• Fine Tuning Valve allows finer production of bubble as required
• Speed control
• Best accessorized reactor in the market

Product Specifications:

Dimensions	16 x 7 x 6 inches
Weight	2721 grams
Weight of boxed product	Same
Capacity	Upto 4 Liters

15. Best for Aquariums: TAAM Rio 90 CO2 Reactor

This is the perfect CO2 reactor for big tank plants and fish – it gives perfect CO2 dissolution, ultra-fine bubbles and a crystal clean look to your tank plants.

This reactor also has a built in skimmer, so any algae or other debris floating at the top of the tank is automatically cleaned up. The filter pad catches very small debris that would otherwise escape a regular cleaner.

The reactor itself is very easy to clean as it can be conveniently dismantled, cleaned and maintained as it can be dismantled completely.

If you seek high performance, then this is the best choice.

Key Features:

• Dual Reactor and Skimmer
• Made of sturdy material

Product Specifications:

Product Dimension	0.1 x 0.1 x 0.1 centimeters
Product Weight	294 grams
Weight of boxed product	340 grams
Capacity	90 to 250 gallons

Buying Guides

Here, I have put together some necessary things you might want to consider before buying a reactor. Read on and understand how to find the perfect product.

Fish Tank Size

How large is your fish tank? It’s important to keep in mind that not all reactors are able to work for all sizes. Reactors are supposed to diffuse 100% of the CO2 and if the size is bigger than its capacity, the quality is compromised.

So measure your fish tank capacity and then check the reactor’s packaging to match the capacity it is suitable for.

Ease of Installation

Fishes are very sensitive creatures and it is important to note that moving them too often can cause traumatic experiences for them that negatively affects their wellbeing. While considering a reactor, think about how easy it will be to install and how much of a disturbance it will cause for your fish.

Affordability

The fact of the matter is, not everyone has the kind of money to spend on their hobbies – we have so many other things happening in our lives that we can’t always pay top-dollar for things. That being said, it is important that when you’re looking for a CO2 Reactor, you pay a reasonable price for it.

A good CO2 Reactor – as we’ve seen with some of the examples given – does not need to drain your wallet; so make sure to compare prices before making your selection.

Leakage Free

One of the few problems that CO2 Reactors can cause you is leakages. This can be due to a variety of reasons, one of which is incorrect installation or because the pipes are too big or too small. To rectify this, some reactors have attached ‘leakage proof’ o-rings that adjust for size differences and prevent leaks.

So when shopping around, check to see if the CO2 Reactor you fancy comes with a ‘leakage proof’ system in place or if you need to buy the necessary equipment to stop the leaks yourself.

Necessary Components To Set Up A Reactor?

An ideal CO2 kit comes with the reactor, top quality tubing, suction cups, valve and a pressure gauge. Moreover, the tank owners; particularly, love to find ceramic replacement dishes in the kits, the perfect solution to their tank cleaning concerns.

Make sure to check the parts available with the reactor, as you would be required to fit some extra pipes or hoses to secure your tank glass against the reactor and protect the floor from any leakage.

CO2 Reactor Vs. Diffuser – What Is Best For My Fish Tank?

Although both are CO2 regulators, may beginners get confused between a reactor and a diffuser. Let me explain some major differences for you understand.

Diffusers

• These are CO2 regulators that offer supply of CO2 to the tanks by breaking down the bubbles into tiny bubbles.
• These are good for small and medium sized tanks.
• Diffusers are good distributors of CO2 in the tanks, but they are mostly not 100% efficient.
• These require to be soaked to clean, which is a difficult task for most users.
• It also creates a mist-like diffusion. Some people tend to dislike this misty look.

Reactors

• These are CO2 regulators which provide 100% CO2 dissolution.
• Unlike the diffusors, they do not release CO2 in the tank directly; but they mix it with tank water within the reactor before they release it.
• They do not create a misty spray of bubbles, keeping the aquarium clear.
• Due to their availability in different sizes, they are good for tanks of various sizes.
• These are very easy to clean as they can be taken apart conveniently.

What Is The Best Way To Maintain My CO2 Reactor?

The right installation is the most important factor in the performance. Make sure you follow step by step instructions given on the package. Always try to dip the hose and tubes in warm water before you try to slide them on to avoid breakage.

It is also best to place the reactor closer to the bottom of the tank for best results. Water and chlorine bleach together can work wonders for a reactor’s maintenance. Simply soak the reactor into the solution and then rinse and wash under clean.

Frequently Asked Questions

Once you have decided on the perfect reactor for your fish, here are some questions answered that might be bothering your mind.

Where should the reactor be placed within a fish tank?

It is advised that the right placement is as low as possible to keep the flow longer in the tank’s water current.

How do I circulate CO2 in my planted aquarium?

There are two ways for you to ensure the circulation of CO2:

• Use two smaller diffusers at both ends of the tank with their canister.
• Manage the movement of water with power heads fitted in the tank.

Is too much CO2 harmful for my fish?

Too much CO2 can cause a drop in the pH levels, which is toxic for the fish. It is best to find out what kind of the ppm levels are best for the fishes you have in your aquarium and set the levels likewise.

How long should I run my CO2?

The best practice is to regulate the CO2 to start after an hour of when the lights turn on and one hour before the lights turn off. Ideal detection is to note what duration is required for 1.0 pH drop.

Conclusion

If you are going to invest in a CO2 reactor for your aquarium, then it is probably best to get a good one. A good CO2 reactor provides maximum performance. Along with good performance, it should also be pocket-friendly and within your budget. I hope the list helps you find the best one for you.

For me, the best CO2 Reactor for medium and large sized tank is Gulfstream Tropical AGU00528 Ista Max Mix as it has enhanced functionality, best supply, and durability for a decent sized aquarium that doesn’t need too expensive devices.

If you find yourself feeling bad about not investing in a CO2 reactor before, don’t feel bad! You are taking the first step in ensuring the good health of your plants and fishes. And that is what matters the most!