7 Best CO2 Controllers for Grow Rooms and Grow Tents

A CO2 controller is a device that manages the carbon dioxide (CO2) level in a greenhouse or indoor grow room.

The CO2 controller works by continuously monitoring the levels of CO2 in the growing space. When CO2 levels drop below a preset level, the controller triggers the release of more CO2 (usually from a connected tank or burner), maintaining an optimal environment for plant growth.

In combination with a CO2 regulator, the CO2 controller plays a critical role in automating the addition of CO2 to the grow space. The regulator controls the flow rate of CO2 from the source, while the controller monitors and adjusts the CO2 concentration in the environment based on pre-set levels.

The main benefits of using a CO2 controller include enhanced plant growth, provide consistent CO2 levels, and save more energy for indoor growers. 

When choosing a CO2 controller, consider the data reading accuracy and ease of use first. Your CO2 controller must provide precise data to ensure your plants are in the optimal range and prevent major accidents and plant death. If it’s versatile and adjustable, you can easily use it for your growing needs. Such factors ensure you get high-quality and effective products for healthy plants. 

1. Lyonsyst CC201 CO2 Monitor and Controller – Best performance 

The Lyonsyst CC201 CO2 monitor and controller offer dual working modes with a built-in sensor for both day and night.

The system notifies the users when the readings show too much or too little CO2 concentrations. The growers should adjust the levels to reach the optimum standards (increase/decrease CO2 readings, temperature, and humidity). 

This CO2 controller contains a large LCD monitor with the maximum or minimum values previously recorded. So, even if indoor growers change the set indoor conditions, they know the previous levels of management. 

The Lyonsyst CC201 CO2 monitor also uses a built-in nondispersive infrared sensor (NDIR) to measure the optimal CO2 levels (1000-1200 PPM) to prevent higher concentrations from causing intoxication and even explosions. 

Due to its sensor system, the Lynosyst CC201 CO2 monitor works from a 15 ft distance, calibrating the sensor independently. 

This controller is rated 5/5 by our reviewers due to its precise readings and versatility for greenhouses, hydroponics, and grow tents. The price is affordable for many indoor growers. 

Pros: Ease of use and installation with standard CO2 tanks, adjustable for safe use 

Cons: Shipping issues, as it comes broken

2. Autopilot APC8200 CO2 w/15′ Remote Sensor Monitor & Controller – Best system technology 

The Autopilot CO2 controller provides precise readings for minutes, hours, days, and weeks to get accurate CO2 levels. 

Thanks to its manageable Trend Chart Zoom levels, the Autopilot CO2 controller traces and stores the previous seven-day readings, and indoor growers can compare them. 

The CO2 controller uses a 15 feet long cable, covering all angles in the grow room. This way, you get precise readings in all grow room locations. 

The Autopilot CO2 controller uses an adjustable monitor with a remote sensor, giving you various functions, such as zooming, night or day sensor, NDIR readings, etc.

The Autopilot CO2 controller uses an alarm system to prevent accidents and poisoning when the CO2 levels are too high.

This controller comes with solid and durable construction made of waterproof and anti-corrosion plastic material, so it has a prolonged lifespan.

We rated it at 4.5/5, mostly due to its ease of use and adjustable functions. But its price is high, so it’s not affordable for all users. 

Pros: Back home functions in case of a user setting error, reliable for longer use

Cons: No app for phone control; you must install it alone 

3. Titan Controls Atlas 2 Preset CO2 Monitor/Controller – Best Accuracy

The Titan Controls Atlas 2 CO2 controller is a versatile tool suitable for indoor growing areas, such as grow tents, grow rooms, hydroponics, etc. 

Titan Controls Atlas 2 CO2 does not require any assembly. Indoor growers simply plug it into the CO2 tank via a powder cord. It works with regular CO2 tanks with 20-50 lbs.

The Titan Controls Atlas 2 CO2 controller offers a preset CO2 control at 1500 PPM. When the levels are higher, the alarm system notifies you to change the indoor growing conditions. 

Thanks to its self-calibration feature and built-in photocell system, this controller allows CO2 enrichment only during daylight, so there is no fear of higher concentration during the night. 

The Titan Controls Atlas 2 CO2 controller lasts for almost 10 years because it provides a durable and solid powder-coated steel closure. 

We rated this CO2 controller at 4.5/5 thanks to its convenient use and pre-assembled system. But it comes with a higher price tag and doesn’t offer prime shipping. 

Pros: Sturdy and reliable for more extended use, it doesn’t require calibration. 

Cons: Package issues, as parts might be missing 

4. DANOPLUS CO2 Controller Carbon Dioxide Controller – Best versatility 

The Danoplus CO2 controller is ideal for its accurate daily and night readings. The double-reading mode ensures the CO2 levels are optimal to prevent accidents and malfunctions. 

The built-in alarm also notifies you when the CO2 levels exceed the allowed threshold. 

You can install and use this CO2 controller easily since it comes pre-installed, and you just have to plug it in with the power cord. Its piggyback socket is suitable for standard regulators, generators, and CO2 tanks with 20-50 lbs capacity. 

Thanks to its wide LCD screen, this CO2 controller records the CO2 charts and levels per minute, hour, day, or week.

Due to its piggyback design with holes and hangers on the back, you can mount the Danoplus CO2 controller on the wall for ease of use. 

We rated this CO2 controller at 4.5/5 since it comes pre-assembled and offers precise readings. It also has an average price, not that expensive. 

Pros: Quick setup and flexible use, durable design for longer lifespan 

Cons: Green lights stay on even during the night 

5. TEKCOPLUS CO2 Controller Carbon Dioxide Monitor – Best safety features 

The Tekcoplus CO2 controller uses the built-in NDIR sensor that shuts off the controller during the night to increase safety standards and prevent accidents. 

In addition, this built-in photo sensor offers a dual working mode – both day and night detection, and allows for daily, hourly, and weekly readings and storage. 

Its design allows you to get accurate readings 4.5 meters away from the controller, thanks to its long power cord. 

Its touch-screen functions, such as auto-power off and on, turning LED lights on and off, and setting time scales for hours, days, etc., allow you to change indoor conditions and keep plants healthy. 

As the Tekcoplus controller uses zone value and CO2 control value, it’s ideal for customizable settings and covering all parts of the grow room and indoor plants. 

Its programmable system also allows you to restart it when you notice an error in the readings or system. 

You can also choose either human-zone or plant-zone mood to ensure the proper CO2 levels in indoor places. 

We rated it at 4.5/5, mostly for its quick setup. The price is also budget-friendly. 

Pros: Durable for a longer lifespan, easy to use and manage 

Cons: Their customer service is not so reliable 

6. EDYCARX Carbon Dioxide Controller – Best design

The Edycarx CO2 controller comes pre-installed, so you don’t need extra tools, such as power cords, cables, or fixtures, to set it up. You can mount it on the wall to get accurate readings. 

This controller is suitable for its adjustable functions, such as zoom-in readings, turn-on sensors, and alarms, to keep the safety standards advanced. 

The Edycarx controller uses both day and night modes, shutting off the unit at night to prevent increasing CO2 levels when the lights are off. 

Choose among human-zone and plant-zone modes to ensure safety standards for both humans and plants and keep the CO2 levels optimal without poisoning or plant damage. 

The Edycarx CO2 controller has a remote sensor probe, a photocell system, and a 15 ft data cable to let you control the indoor situation in your grow tents from all angles. 

We rated it at 4.5/5 due to the quick setup system, and its price matches the quality.

Pros: Added ventilation system for optimal temperature; it comes pre-assembled 

Cons: Package issues as the unit comes damaged and scratched 

7. Gain Express CO2 Monitor Air Quality Monitor for Carbon Dioxide – Best quality 

The Gain Express CO2 controller uses the built-in-relay function to control the ventilation system and automatically maintain the CO2 levels you set or specify. 

When the CO2 levels surpass the set standard, the alarm goes off, notifying you that you must modify the indoor conditions.

Due to its built-in NDIR sensor, the Gain Express CO2 monitor also provides accurate and long-term readings. It also performs readings by minute, hour, day, or week, stores the data, and allows you to compare them for the best results.

Its power supply includes a 12V AC power adaptor, and the system works with either 120V or 240V power input. 

Due to its versatility – compact size and weight of only 14.4 ounces, you can install and adjust this controller in grow rooms, grow tents, and greenhouses. 

This CO2 controller comes already pre-assembled, so it doesn’t require any additional tools for its setup, such as cables, power cords, fixtures, screws, etc. You can mount it on the wall and control the readings in all corners of the indoor growing area. 

This controller is rated 4/5 by our reviewers as it prevents accidents due to the safety system.

Pros: Safety features to ensure security, versatile and easily adjustable for optimal use

Cons: The adapter doesn’t function properly

How to Choose the Best CO2 Controller?

To choose the best CO2 controller for your grow tent, consider versatility, safety features, functionality, installation and ease of use, warranty, and price. 

Versatility: Choose the CO2 controller with switchable human-zone and plant-zone modes to adjust the settings and ensure optimal CO2 levels for both plants and animals. This way, you prevent explosions and poisoning accidents for humans and plants.  

Safety features: Look for CO2 controllers with built-in NDIR sensors and shut off the controller automatically at night to avoid higher risks of more CO2 concentration. Also, look for models with built-in alarms to change the settings when the alarm goes off immediately. 

Functionality: Best CO2 controllers have data storage and readings covering every minute, hour, day, or week. Search for such models, as you can compare the reading data to ensure the proper standards for indoor growing plants. 

Installation and ease of use: Consider pre-assembled models (as many units are listed in our reviews), as these products ensure the quickest setup process and don’t require extra tools for installation. You can mount them on the wall and get precise readings without any complex procedures. 

Warranty and price: CO2 controllers come in higher price tags, so choose the quality first and then check for the prices. The quality includes safety standards, various functions to turn the autopilot on/off, setting the readings hourly, weekly, daily, etc., and durability. Also, look for models with at least a one-year warranty, as you can replace them if something goes wrong. 

Why use a CO2 grow controller?

You should use a CO2 grow controller to ensure optimal CO2 for the grow tent, usually between 1200 and 1500 PPM. 

CO2 controllers allow for the timed release of CO2, ensuring that it is only released when necessary (typically when the lights are on and the plants photosynthesize), saving resources and costs.

CO2 controllers help maintain safe levels in the grow tent, protecting both the plants and the grower from higher CO2 concentrations. If the CO2 levels surpass the allowed threshold, they negatively impact the surroundings, causing health issues and plant decay. 

Increasing CO2 levels without control has harmful effects on both the environment and human health. Increased carbon dioxide concentrations cause smaller stomatal apertures in plants, decreasing leaf conductance for water vapor, as the US Department of Agriculture explains. 

From a human health perspective, exposure to high levels of CO2 can produce various health effects, such as headaches, dizziness, restlessness, and a tingling sensation. In extreme cases, high exposure to CO2 even leads to unconsciousness, coma, or convulsions, according to the Wisconsin Department of Health Services.

On a broader environmental scale, increasing CO2 and other greenhouse gases reduces the Earth’s ability to cool itself off by radiating energy into space. It contributes to global warming and climate change, as the Columbia Climate School states. 

While increases in CO2 make cereal crops grow more quickly, higher CO2 concentrations also reduce the nutritional value of these crops. So, while CO2 is beneficial for plant growth, it’s crucial to maintain balanced levels, according to the research called “Increases in atmospheric carbon dioxide: Anticipated negative effects on food quality” at the National Library of Medicine. 

How to set up a CO2 controller in a grow tent?

To set up a CO2 controller in your grow tent, place it in a suitable location, connect it correctly to the CO2 tank and power source, then set its working mode. 

Place the controller at plant height since CO2 is heavier than air. The controller should be away from vents or fans to avoid inaccurate readings.

Connect the controller to a power source and ensure it’s functioning correctly.

How to use a CO2 grow controller?

To use a CO2 grow controller, install it properly in the grow tent, target the optimal levels and monitor them, and ensure your grow space is well-ventilated. 

Install the CO2 emitter (CO2 tank or CO2 burner) above the canopy of your plants.

Set the standard CO2 levels. The standard amount of CO2 for vegetative stages is between 800 and 1200 ppm. For the flowering stage, the optimal CO2 amount is 1200-1500 ppm. 

You should time the release of CO2 to coincide with your lights-on period. Set the timer to release the CO2 levels only during the daytime. 

Check and maintain the optimal CO2 levels regularly. 

Ventilate your grow space to replenish oxygen levels and prevent the buildup of excessive humidity. 

How to prevent your CO2 from harming your plants?

To prevent your CO2 from harming your plants, maintain optimal CO2 levels. Use a CO2 controller to achieve optimal CO2 levels. 

Ventilate your grow rooms, as regular ventilation prevents the buildup of excessive CO2 and humidity, both of which harm plants. 

Keep an eye on your plants for any signs of stress or poor health, as such conditions indicate that the CO2 levels are too high.

Use CO2 cycles only during the daytime for optimal photosynthesis. Releasing CO2 during the dark cycle leads to excessive levels that harm plants.