Growing cannabis is far from complicated due to so many reasons.

Yes, there is temperature, air, water and etc. but what about CO2?

Cannabis requires by far more CO2 than it is present in the air normally. For example, at the moment, CO2 is 400 PPM (parts per million).

Yes, there is a lot of info which suggests that the value is 350 PPM, but all of those sources are obsolete, so the first value here is accurate.

Now you must know that in order to get the best yield and far more buds than usual, you will have to increase the CO2 significantly.

That’s why you will need the best CO2 regulator.

Why Cannabis Growers Need CO2 Regulators?

The first and the main reason why you need a CO2 regulator is the fact you will be able to increase the levels of CO2 in the controlled environment.

As we have mentioned, the current levels are 400 PPM, which isn’t nearly enough for your cannabis. It will need around 1500 PPM.

Furthermore, the levels of CO2 will oscillate daily for 10-15 PPM, which is something cannabis doesn’t like either.

In the simplest meaning of the word, CO2 regulators control and maintain the needed values of the CO2, therefore the name.

They are essential for getting strong and healthy cannabis and they can make a true difference.

In order to understand how much they are actually helpful, try to remember that with CO2 regulators, you will get 30% more buds.

Sounds interesting? But, this isn’t all.

Buds and the cannabis, in general, will provide a much better overall quality and they will be more desirable.

Without a CO2 regulator, nothing of this is possible.

Now you may believe that some alternatives are great and they work like a charm. For example, you can use dry ice or mushroom boxes. Of course, they are more than just affordable, but they are not something you will want to use.

In plain words, they are not sufficient when it comes to providing a suitable level of CO2 to cannabis. Yes, you will increase the levels of the gas, but it will still be lower than needed.

There are a lot of different CO2 regulator types.

We determined that the two most popular types are pre-assembled units which are ready to use straight away and the models which have to be assembled. They offer more freedom with the overall result and they are more focused for professionals.

Next, there are two versions when it comes to generating CO2.

The first type will burn propane or butane in order to produce CO2, while the second type will use a CO2 tank.

Those which burn gas require less maintenance, but they generate heat. Those with CO2 tanks are safer, but the tank must be replaced all the time.

A timer feature is needed as well.

However, it is useful only with the second type CO2 regulators.

A timer will release the CO2 in perfect amounts each couple of hours when the plants need it the most. It eliminates the risk of spending time in a room where CO2 levels are too high for humans.

On the other hand, it delivers the most suitable amount of CO2 to cannabis, so the plants will benefit from it.

In a nutshell, CO2 regulators are used to provide ‘’oxygen’’ for the plants.

Cannabis breathes the CO2 while produces oxygen. In a closed environment, CO2 levels will be lower than usual, lower than the plants actually need, so they won’t be able to breathe sufficiently.

CO2 regulators simply eliminate this issue and allow for the cannabis to get plenty of CO2.

In return, growers get more buds and a better yield.

Main Factors to Consider

CO2 regulators consist of three parts, a regulator, tank, and a controller.

The controller is used for scheduling the CO2 release, while the regulator determines how much of CO2 must be released. The tank is obviously used to store CO2.

All of this looks simple, but there are a lot of factors to consider when buying the new CO2 regulator. Below are the main factors each grower needs to take into consideration.

CO2 Monitor

Sadly, most CO2 regulators come without a monitor, but we believe it is essential.

This addition will monitor the levels of CO2 in the grow room. Because this gas is toxic to humans, a CO2 monitor is almost mandatory.

Most new models come with this addition, but it is still far from the standard element.


All-metal construction is mandatory, but which material to choose from?

There are countless options, but in this case, the oldest is the best. Brass CO2 regulators are still the best and rated as the safest of them all.

This type of construction is reserved for premium models and professionals, so you will definitely want to consider it.

Type of a CO2 Regulator

We already have mentioned that there are 2 main types of CO2 regulators.

The first type urns propane or butane to generate CO2, while the second type uses a CO tank. In the lack of a better word, the second type here is better.

It is a much safer alternative, for the plants and growers and they are relatively affordable. The first type is fine, but you will need more attention and you will need to look at the heat output.

It isn’t a coincidence why the second type, those with CO2 tanks are more popular and more desirable. Just keep in mind that the CO2 tank must be replaced or recharged frequently.

Cubic Feet per Hour

Cubic Feet per Hour or CFH is something which must be seriously taken into consideration. It represents how fast a regulator will release the CO2 into the grow area.

Now, there are a lot of variations, but most of them will vary between 0.5 and 15. The trick is, these are industry standards. Anything more than 15 is reserved for professional, commercial applications and anything less than 0.5 is for low-end applications.

PSI rating

A pressure rating can make a huge difference. It represents the value, the maximum one a tank can withstand pressure.

Keep in mind that the pressure will fluctuate all the time, and it depends on multiple factors, including the temperature.

At the moment, the value you would like to see is 4000 PSI. Of course, this is the maximum possible pressure a tank can withstand. All tanks with a capacity of 20 pounds have an average pressure of 800 PSI.

Metabolic Rate Increase

The factor we have here is focused on the plants rather than on the CO2 regulators. It represents the overall metabolic rate which will be increased when the CO2 regulator is used.

Average models can provide between 15 and 25% improvement, but premium one can reach 40%.

As obvious as it sounds, this is the main factor to consider when it comes to the overall success of the yield. The more, the merrier. Interesting: An average score is around 30%.


Tubing and hoses have a huge role in the overall productivity of a CO2 regulator. There are two main sub-factors to look for. The first one is the material of the tubing. They should be made from high-quality plastics. The second sub-factor is the length of the tubing and hoses.

It should be 5 meters or more. Yes, there are a lot of versions with shorter hoses and tubes, but in a case or when you need a longer system, you will have to purchase all of this additionally, so it is a much better choice to get long tubing as soon as possible.

As we have mentioned at the beginning of the section, yes, CO2 regulators are simple, but getting the best one isn’t. There are a lot of factors to consider and a lot of elements to take into account.

All of the points we have mentioned above is equally important, so don’t try to skip one or two.

5 Best CO2 Regulators

1. GROW1 CO2 Grow Room

This is the best CO2 regulator most professionals use nowadays. It is well-made, comes with all you are going to need and it has a long warranty.

The flow meter is easy to use and it ranges between 0.5 and 15, which as we have mentioned is industry standard. Dimensions are 6 x 7 x 9 inches and the weight is 3 pounds.

As you can see, there is no anything special about this model, which is a great thing.

It is a high-quality alternative compared to other models available right now and it will last for a long period of time.

What’s more, can be said about this unit is that it is designed and made by one of the best brands in the industry.

You definitely won’t make a mistake choosing it.

All-metal design
Long warranty
Full and easy to adjust flow meter
For professional purposes

2. SPL (Co2) Regulator Emitter System

This may be the best CO2 regulator for you as well. The main advantage here is in the accuracy this unit provides.

We must say that it is one of the most accurate models available on the market today.

As such, we must recommend it for growers who have a high attention to the details and who always want the best and the most precise CO2 delivery to their plants.

Furthermore, this is a high-end unit, so it can reduce the harvest time for 50% and it will boost the overall result.

When it comes to materials, there is no much to say.

It is made from brass, the Solenoid Valve is optimized for heavy-duty applications and the regulator comes pre-tested.

As a matter of fact, the entire unit is tested before delivery. Try to remember that the flow meter here is 0-15 scfh.

Made from brass
Supreme accuracy
Reduces harvesting time for 50%
Has a positive effect on the buds
You will probably need a power cord adapter to use this unit

3. MANATEE Co2 Regulator Hydroponics Emitter System

Straightaway, we can see some impressive benefits of this unit.

The first one is in the overall quality, which is exceptional. Then we have the fact yield will be increased for 40%, which is, if you recall one of the best results overall.

Solenoid valve is an industrial-grade unit, so you can get a better info regarding it.

Other facts you should know is 5 meters long hose, improved precision, and durability.

Still, this is one of more affordable units on the market, so it is a great choice for those who are on a tight budget.

Specifications include 100.000 hours of lifespan, 4.000 PSI of pressure it can withstand an operating temperature between 32 and 120 degrees Fahrenheit.

Basically, you will have a CO2 regulator which is more focused on industrial applications than for indoor ones, but it is affordable, so it wouldn’t be a smart decision not to list it here.

4000 PSI
100.000 hours of lifespan
Industrial-grade solenoid valve
All-brass construction
Long tubing
Increases yield for 40%
User manual is useless
Valve may require some adjustments

4. VIVOSUN Hydroponics CO2 Regulator Emitter System

In the lack of a better word, we must say that this unit is probably the safest alternative here.

It is based on the latest technology, therefore, all standard and important factors are already met.

For example, it will withstand 4.000 PSI of pressure, it will boost the yield for 40% and this small CO2 regulator is going to last for a long period of time.

One, interesting advantage of the unit in question is the CO2 regulation. It is supreme and probably much better than any other can provide. Flow regulator is standard and it offers 0-15 scfh.

Tubing, brass design and the gauge are all pre-tested, adjusted and ready to be used as soon as they are delivered. In other words, you are getting a CO2 regulator which can be used as soon as you need it.

Packaging is discrete and the customer support is excellent.

Overall a great CO2 regulator
Flow regulator
40% yield improvement
Loud while operating
Complicated to adjust

5. CO2 Generator – Liquid Propane LP – Autopilot APCG8LP

The first thing and the most obvious one you should know is that this is a propane CO2 regulator.

It means that it will burn gas in order to provide CO2.

Among the models of the same type, this is the best CO2 regulator.

Yes, it is still a member of the propane CO2 regulators, which are more focused on high-end requirements, but it is cleverly made, so this compact unit has a lot to offer.

It comes with an autopilot feature, meaning that the unit will regulate the entire list of requirements all by itself.

Then it has a flip safety switch which will turn off the unit in a case of flipping.

All burners are made from brass and they are more than just accurate.

The best propane CO2 regulator
High-end unit
Autopilot feature
Easy to use
Flip safety switch
Less safe than tank-based CO2 regulators


Here is the best CO2 regulator each grower will need at some point. These models have been properly tested, checked and rated according to their specifications.

In general, each model from the list will be more than just ideal for you and your plants. And yes, all of them are safe to use indoors.