Best Aquarium CO2 Regulator (2024 Buyer’s Guide)

Featured Image - co2 regulator for planted aquarium
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: June 10, 2024
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A CO2 regulator is an essential device for safely and precisely introducing carbon dioxide into your planted aquarium. It helps control and reduce the pressure of CO2 tanks or vessels to avoid under or over-saturation in your aquarium. However, the vast range of options on the market can make choosing the perfect CO2 regulator for a planted aquarium quite challenging. Moreover, taking into account factors such as price, features, and the quality of the device is crucial in making the right choice for your aquarium.

Article Summary

  • A CO2 regulator is vital for safely injecting carbon dioxide into planted aquariums.
  • Choosing the right CO2 regulator involves considering factors like price, features, and quality.
  • Top Pick: Titan Controls CO2 Regulator praised for quality, solenoid valve, and flow accuracy; Best Value: FZONE Aquarium CO2 Regulator affordable with dual pressure gauges and automatic timer system; Editor’s Choice: SR Aquaristik Dual Stage Co2 Regulator Kit commended for precision, safety features, and solenoid valve.

In this article, I’ll be covering the best CO2 regulators for planted tanks to make sure you choose the correct one for your setup. I’ll also be going over some important information about these devices in general to help you understand how they work.

Let’s get started!

Best Co2 Regulators for Planted Aquariums

Top Pick

Titan Controls CO2 Regulator

The Titans Controls CO2 Regulator sports a durable solenoid valve, pressure gauge, and brass construction to provide accurate dispersion of carbon dioxide in your planted tank.

Top Pick: Titan Controls CO2 Regulator

One of the best CO2 regulator for planted aquarium is the Titan Controls CO2 Regulator due to its high-quality brass construction, robust oilless pressure gauge, and heavy-duty solenoid valve.

It boasts an accuracy flow meter of between 0.5 and 15 SCF (standard cubic foot) per hour, which is ultra precise to give you a correct reading. It also comes with 2 plastic washers and a 12-foot CO2 dispensing line.

This works with the Titans Controls CO2 Controller as well as other 120-volt CO2 controllers and timers.

One of my favorite features of this regulator is how easy it is to use. It’s simple to set up and install thanks to its informative instructions!

The only downside of this regulator is that the pressure gauge can sometimes give a low reading. However, the reading is only slightly off, so I don’t think it’s a huge issue, especially if you use a separate CO2 pressure tester.


  • Weight: 2.9 lbs
  • Material: Brass
  • Dimensions: 10.4” x 8.4” x 6.1”


  • Easy to use
  • Strong solenoid valve
  • Robust pressure gauge
  • High-quality brass construction


  • Pressure gauge reading can occasionally be a little low
Best Value

FZONE Aquarium CO2 Regulator

The FZONE CO2 Regulator is a solid choice for aquarists on a budget. It comes with dual pressure gauges, a split-type solenoid, fine-tuning valve, and an automatic turn on/off system with a timer.

Best Value: FZONE Aquarium CO2 Regulator

If you need a good-quality but affordable CO2 regulator for your planted aquarium, the FZONE Aquarium CO2 Regulator is a solid option due to its very reasonable price. It features dual pressure gauges to provide you with a more accurate reading of carbon dioxide.

It has a split-type solenoid, which is more reliable and safer to use than AC models. The device has a fine-tuning valve with knurling, which allows you to make fairly accurate and easy adjustments to the CO2 pressure output.


I really like that this regulator has an automatic turn on/off system and timer so you can set how long you want carbon dioxide running in your tank. I also like that the regulator is made out of tough aluminum alloy as this makes it less prone to rust.

The FZONE Aquarium CO2 Regulator has its own bubble counter with a check valve, as well as all the tools you need to set up the device.

The main downside of this carbon dioxide regulator is the slight inaccuracy of the fine-tuning valve. The unit can also sometimes be prone to leaking after around 9 months of use, but the product does come with a 12-month warranty!


  • Weight: 1.7 lbs
  • Material: Aluminum alloy
  • Dimensions: 9.49” x 7.05” x 3.5”


  • Dual pressure gauges for seamless operation
  • Automatic turn on/off system and automatic timer
  • Made out of aluminum alloy for increased durability


  • Can leak within the first year of use
  • Fine-tuning valve can be a little inaccurate
Editor’s Choice

SR Aquaristik Dual Stage Co2 Regulator Kit

The Aquaristik Dual Stage Co2 Regulator Kit offers dual gauges for optimal precision and reliability, alongside an electric solenoid valve, accurate needle valve, and safety valve.

Editor’s Choice: SR Aquaristik Dual Stage Co2 Regulator Kit

One of my personal favorite CO2 regulators for a thriving planted aquarium is the SR Aquaristik Dual Stage Co2 Regulator Kit as it boasts superior quality and accuracy.

It has a dual-stage valve for precision and safety, and also displays the canister pressure and CO2 output. I like that the device has a large control output knob as this prevents you from accidentally changing the output!

It features an on/off solenoid valve that is compatible with a pH controller or timer, as well as a bubble counter and extra regulator seals (this is always useful!).


This dual stage regulator has a high precision needle valve, alongside a bubble counter with a built-in valve and a safety valve. The latter is really convenient as the valve will automatically release high pressure inside the device if it exceeds its limit.

Last but not least, the electric solenoid valve has a cool operating temperature while using minimum power, making it energy efficient.

My only gripe with this dual stage regulator with two gauges is that it can be a bit difficult to set up initially as it doesn’t come with any instructions. Fortunately, the video below explains how to install and use the device, so the lack of instructions isn’t a huge problem!

SR Aquaristik Dual Stage Co2 Regulator


  • Weight: 8 lbs
  • Material: Not specified
  • Dimensions: 12.68” x 9.13” x 7.17”


  • Precise needle valve
  • Cool touch solenoid valve
  • Two-stage valves for accuracy
  • Automatically releases built up pressure


  • Doesn’t come with instructions

FZONE Pro Series Aquarium Dual Stage CO2 Regulator

This CO2 regulator from FZONE features dual stage design and adjustable pressure output to give you full control of the amount of CO2 you use.

FZONE Pro Series Aquarium Dual Stage CO2 Regulator

Another one of the best aquarium CO2 regulators is the FZONE Pro Series Aquarium Dual Stage CO2 Regulator. It sports a multi-stage design and an adjustable output pressure, the former of which allows for stable CO2 pressure no matter the amount of carbon dioxide leftover in the canister.

This is ideal for preventing issues like an end-of-tank-dump and allowing for more precise output overall. You get two manifold blocks with the device – each one has an ultra-accurate needle valve which can be used independently, so you can use them on a single tank or two aquariums.

The regulator has a built-in safety valve that automatically releases pressure once it goes over 100 PSI, which is another great feature. The DC solenoid valve operates quietly and is completely safe to touch, too!

Unfortunately, the needle valves for this CO2regulator are difficult to adjust. The pressure gauges can also be a little inaccurate as they have a fairly limited range.

It’s also important to note that this carbon dioxide regulator is not compatible with paintball tanks.


  • Weight: 2.43 lbs
  • Material: Aluminum
  • Dimensions: 7.56” x 2.56” x 6.69”


  • Features two gauges
  • Built-in safety valves
  • Silent solenoid valve
  • Comes with two manifold blocks that can be used independently


  • Needle valves can be hard to adjust
  • Pressure gauges lack precision and range

FZONE Aquarium CO2 Regulator Mini Series

The FZONE Aquarium CO2 Regulator Mini Series is an excellent choice for a small planted tank as it’s designed with nano tanks in mind. It features a precision flow meter, dual stage decompression, and a rotatable needle valve.

FZONE Aquarium CO2 Regulator Mini Series

The FZONE Aquarium CO2 Regulator Mini Series is designed specifically for smaller tanks, so it’s a great option if you have a planted nano tank. It’s made with the same quality and top-notch aluminum alloy as the other FZONE CO2 regulators I’ve reviewed, with the bonus of being compatible with a paintball tank.

The regulator has dual stage decompression with an adjustable output pressure and CO2 flow rate. It has a 12V DC solenoid valve with a rotatable copper needle valve to allow you to fine-tune the flow.


You get a bubble counter included with this two stage regulator, as well as all the necessary tools to set it up! The device operates quietly and at a low temperature, and even features an indicator bulb so you know when it is actively working.

However, this CO2 regulator for nano planted tanks can leak after a few months of use. It does come with a 6-month warranty, so you can get a replacement if you encounter this issue.

The drop counter can also be a bit unreliable as it needs to be re-adjusted every couple of days.


  • Weight: 1.79 lbs
  • Material: Aluminum alloy
  • Dimensions: 6.3” x 6.26” x 3.7”


  • Indicator light
  • Features two gauges
  • Rotatable needle valve
  • Adjustable output pressure


  • Drop counter can be unreliable

What is a CO2 Regulator for Planted Tanks?

CO2 Regulator
CO2 Regulator

A CO2 regulator for planted tanks converts the pressure from CO2 bottles or cylinders into a lower, more controlled pressure so it is safer to use. You can’t use CO2 bottles or cylinders in an aquarium without a regulator, otherwise, you could severely injure yourself and your fish.

In addition, you’ll need to use either a single stage or dual gauge CO2 regulator designed for aquariums – industrial CO2 regulators don’t offer precise control of the gas flow rate or a fine adjustment valve.

How Does a Pressurized CO2 Supply System Work?

A pressurized CO2 supply system works by injecting carbon dioxide into your fish tank water, allowing your plants to take advantage of the CO2 to grow healthier, quicker, and more vibrant.

Do Fish Tanks Need a CO2 Regulator?

CO2 regulators aren’t essential in fish tanks unless you have a heavily planted setup that could benefit from the inclusion of carbon dioxide.

Aquarium plants take advantage of CO2 as it encourages growth and is required for respiration, the latter of which is done via photosynthesis.

If you have a lot of live plants in your saltwater or freshwater aquarium and want to use CO2 canisters, a CO2 regulator is mandatory for ensuring you dose carbon dioxide accurately and safely. Planted aquariums with high lighting in particular can benefit from CO2.

However, low-light fish tanks don’t always need CO2 as plants in these conditions don’t typically grow as much – they will also be getting enough carbon dioxide from fish respiration, decaying plant matter, and surface agitation.

Floating plants also can thrive without CO2 as they get carbon from ambient air due to their emersed leaves.

Why Consider Getting a CO2 Regulator?

If you’re planning on adding CO2 to your aquarium, a CO2 regulator will convert the pressure from the bottle or gas cylinder into much lower pressure. This is the main and most important reason why you should get a CO2 regulator.

Without a CO2 regulator, you will not be able to precisely and safely add carbon dioxide to your fish tank.

What Should You Consider When Buying a CO2 Regulator?

Aquarium with Air Pump
Aquarium with Air Pump

A CO2 regulator can be a fairly big investment, so you definitely don’t want to choose the wrong one for your aquarium! Below are a few things you should consider when buying a CO2 regulator for your planted fish tank.

Decompression Stages – Single Stage vs Second Stage?

The pressure reduction in a CO2 regulator for a planted setup has two stages. The first stage decompressures the pressure to roughly three times lower than the pressure in the CO2 tank.

The tank pressure is reduced further in the second stage to a level that can be adjusted via a dial or knob. Single-stage regulators can be difficult to control once the pressure gets higher, so you may need to adjust them more frequently when the cylinder is nearly empty.

Select the Right Material

CO2 regulators for planted aquariums can be constructed out of a variety of materials, though most are made from aluminum, stainless steel, or brass. All of these metals can rust if not taken care of properly, so you should regularly maintain and keep your CO2 regulator clean.

From personal experience, I’ve found that CO2 regulators made from aluminum tend to be less prone to rusting, though it’s still important to take care of your regulator to keep it running efficiently.

Consider Its Compatibility with Other Devices

Another factor to consider is the compatibility of the CO2 regulator with cylinders of different sizes, as well as other devices like a timer, paintball tanks, or pH controller.

Some regulators may only work with CO2 cylinders of certain sizes, so make sure you check whether the unit you’re planning on buying will work with the type of cylinders you want to use.

Make Sure It Contains the Right Inclusions

The last thing you should consider when buying a CO2 regulator for aquarium plants is the inclusions it comes with. These include:

  • Needle valve
  • Bubble counter
  • Gauges
  • Tubing
  • Washers

What Are the Different Parts of an Aquarium CO2 Regulator?

There are a lot of different parts to an aquarium CO2 regulator, from DC solenoid valves to bubble counters. All of these components can be a little confusing to understand if you’ve never used a CO2 regulator before, but it’s important to know each of their purposes so you can set up the unit correctly and fix it if you encounter a problem.

Pressure Gauges

The pressure gauges on your regulator displays the amount of pressure being dispensed by the cylinder and output of the device. Regulators usually have single or dual gauges, though it’s always worth using a regulator that offers dual gauges or double gauges rather than a single stage regulator as it will provide more precise control and accurate reading.

Solenoid Valve

The solenoid valve and a timer on a single stage or dual stage CO2 regulator shuts off the flow of carbon dioxide whenever you don’t need to to run it.

Needle Valve

A needle valve on a single stage or dual gauge CO2 regulator helps control the flow rate of carbon dioxide. It can either be installed inline or to the regulator itself.

Bubble Counter

Bubble counters monitor the level of carbon dioxide coming into your aquarium. A bubble counter should be attached either to your filter tubing or in-line. As you make fine adjustments to your regulator valve, you can check the bubble count to see how many bubbles are entering your tank.

The most effective way of doing this is to count the number of bubbles per second. If you need to reduce or increase the amount of CO2 in your tank, you can do so by decreasing the number of bubbles per second.

Diffuser (In-tank or Inline)

The diffuser on a single stage or dual gauge CO2 regulator allows carbon dioxide to enter the aquarium effectively. The CO2 is dispensed through a porous material that converts the gas into a fine mist of bubbles, which are easier for your aquarium water to absorb.

CO2 Resistant Tubing

You’ll need a few tubes to connect the regulator to the diffuser. The tubing should be CO2 resistant, otherwise, it will make the carbon dioxide useless. Silicone tubing is not suitable for CO2, so make sure you use tubing that is safe to use with CO2.

FAQs About Aquarium CO2

Planted Aquarium

How Does Supplying CO2 Help to Control Algae?

Supplying planted aquariums with CO2 can help control algae as it encourages the growth of aquatic plants, making them both stronger and healthier. This cuts off the amount of nutrients that algae need to thrive.

When aquatic plants are growing well and quickly, algae have less chance to develop and take over your aquarium.

However, using too much CO2 in your tank, especially when paired with too much light, can lead to algae outbreaks that make aquariums look cloudy.

How to Refill Aquarium CO2 Canisters?

To refill aquarium CO2 canisters, simply open the valve on the canister to inject CO2 gas into it. As the canister fills with gas, the pressure gauge will gradually increase. Once you’ve refilled the canister, switch off the shutoff valve.

How Long Does Aquarium CO2 Last?

This greatly depends on the volume of your tank, the size of the CO2 canister, and the number of bubbles per second you run.

For instance, if you’re using a 5-pound CO2 gas canister running at 1 bubble a second, it should last for approximately 3 months.

Aquarium With and Without CO2?

Planted tanks, especially those with high light conditions, benefit largely from the addition of CO2 as it enables plant growth.

Aquarium plants need CO2 for respiration and growth, so adding it to your tank will help your plants be healthier and more colorful.

As a rule, you should use CO2 for any plant species marked as “medium” or “advanced” in terms of care difficulty.

Planted aquariums can still thrive without CO2, particularly those with low lighting and undemanding species. However, plant growth will be slower and less dense, and some plant species may be less colorful.

How Do Aquarium Carpet Plants Do Without CO2?

Carpet plants can do well without CO2 injection, but they will be much less vibrant and lush. However, some carpeting aquatic plants like Glossostigma will not thrive or even survive without the addition of CO2.

How Many Bubbles Per Second of CO2 Aquarium?

The number of bubbles of CO2 you should run per second for a planted tank depends on the size of your tank and the CO2 requirements of your aquatic plants.

As a general guideline, you should run one bubble every three seconds per five gallons of water. So, for example, if you have a 10-gallon aquarium, you should aim to run two bubbles of CO2 every three seconds.

How Many Hours Do You Inject CO2 Into Your Aquarium?

Most aquarists inject CO2 into their planted tanks for 8 hours a day while the aquarium lights are on. There’s no need to use CO2 at night as plants only photosynthesise during the day.


If you’re new to dosing CO2 or are concerned about algae outbreaks, start off with a short duration of CO2 – one hour after the aquarium lights are turned on and another hour before the lights are turned off. You can gradually increase the amount of CO2 to find the right balance for your tank.

How to Measure CO2 In Planted Aquariums

You can measure the amount of carbon dioxide in your planted tank with either a test kit or a CO2 drop checker.

Test Kits

CO2 test kits contain a CO2 indicator liquid and a color checker sheet. Once the test calculates the level of CO2 in your tank water, it will change color so you can compare it against the color checker sheet.

CO2 Drop Checker

A CO2 drop checker is a container that is filled with a fluid that can detect CO2 levels in your aquarium. The liquid changes color depending on the amount of CO2 in your tank. Green is optimal, whereas yellow and blue means there is too much or too little CO2 respectively.

  • High pressure gauge
  • Easy to set up and use
  • Brass construction for durability
  • Comes with a CO2 timer
  • Two-stage pressure gauges
  • Automatic turn on/off system
Best Value
  • Dual pressure valves
  • High precision needle valve
  • Releases built-up pressure automatically
Editor’s Choice

Final Thoughts

I hope this guide helped you select the best CO2 regulators for a planted tank and the benefits of using one on planted aquariums. If you have a heavily planted aquarium, I fully recommend using CO2 with a CO2 regulator to encourage optimal plant growth and color.

Which aquarium CO2 regulators are your favorite? Be sure to let me know on our social media platforms and share this post with your friends and family.

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