The Ultimate Guide to Aquarium Pressure Regulators: CO2 Injection and Plant Growth

Introduction to Aquarium Pressure Regulators

The Role of CO2 in a Planted Aquarium

In a planted aquarium, carbon dioxide plays an essential role in supporting healthy plant growth and maintaining stable biological conditions. Aquatic plants rely on CO2 as one of the core inputs for photosynthesis, converting it into energy that fuels leaf development, coloration, and root stability. Without sufficient CO2, many aquarium plants tend to grow slowly and may show signs of chlorosis or leaf deformation. This makes CO2 injection a common practice among aquarists who wish to create a balanced and visually appealing underwater environment. By maintaining a consistent CO2 concentration, the planted aquarium becomes more capable of sustaining a diverse range of aquatic species while promoting natural oxygenation during the photoperiod. The concept of using a controlled CO2 system has grown significantly, which adds to the importance of understanding the components involved such as an aquarium pressure regulator, CO2 regulator, CO2 diffuser, and other supporting accessories.

The interaction between CO2, lighting, and nutrients forms the foundation of aquatic plant care, and achieving harmony among these factors can greatly influence the visual quality and stability of the aquarium ecosystem. Because CO2 levels fluctuate naturally, especially in closed systems, the need for consistent injection becomes essential to avoid irregular growth patterns and algae imbalance. CO2 systems designed for hobbyists typically include a pressurized gas cylinder, a CO2 regulator, a needle valve, and a diffuser that releases CO2 into the water. With these components working together, planted aquarium conditions can be regulated more precisely, allowing aquarists to tailor levels according to plant species and tank dimensions.

Understanding Aquarium Pressure Regulators

An aquarium pressure regulator, also referred to as a CO2 regulator, is the primary component used to manage the pressure released from a CO2 cylinder and ensure stable delivery into the planted aquarium. Because gas cylinders store CO2 at significantly high pressure, it becomes necessary to reduce and control the output before it reaches the needle valve, solenoid valve, and CO2 diffuser. The structure and function of a pressure regulator determine the stability and consistency of CO2 injection, which directly influences water chemistry and plant growth conditions. A well-designed aquarium pressure regulator helps maintain a steady flow of CO2 throughout the photoperiod and prevents sudden fluctuations that can stress aquatic life.

Regulators used in the CO2 system can generally be categorized into single stage regulators and dual stage regulators. A single stage regulator reduces cylinder pressure to working pressure in one step, making it suitable for many standard aquariums but occasionally subject to end-of-tank dump. A dual stage regulator reduces pressure in two stages, allowing for improved stability and reduced risk of sudden gas release when cylinder pressure drops. The choice between these types often depends on the aquarist’s requirements, the size of the aquarium, and the frequency of cylinder replacement. Regardless of the design, the regulator ensures that the pressure entering the needle valve remains manageable. This arrangement supports fine tuning, contributing to improved control over the flow rate and helping maintain consistent CO2 levels in the aquarium.

The Importance of a Reliable Regulator for Stable CO2 Levels

Stability is a central factor in maintaining a planted aquarium, and the performance of the aquarium pressure regulator directly affects the consistency of CO2 concentration in the water. When fluctuations occur, the plants experience irregular growth conditions, which may result in reduced vitality, weakened stems, or unwanted algae development. A reliable CO2 regulator ensures that CO2 output remains predictable, which is essential for maintaining a balanced relationship between lighting intensity and nutrient availability. Since plants respond quickly to environmental changes, steady CO2 injection can help preserve long-term aquarium health and allow aquarists to cultivate a wide range of plant species with varying CO2 requirements.

In addition to supporting plant health, a stable CO2 level also contributes to the comfort of aquatic animals. Fish and shrimp can become stressed if CO2 levels spike suddenly during the photoperiod. The regulator works with supplemental components such as the solenoid valve, which automatically shuts off CO2 supply during the night, preventing excessive accumulation when plants stop photosynthesizing. A trustworthy regulator therefore becomes an essential part of creating a safe habitat that takes into account both plant and animal needs. Consistency in pressure output also reduces the need for frequent adjustments, making aquarium maintenance more manageable.

Components Commonly Associated With a CO2 Regulator

The aquarium pressure regulator is typically connected to multiple components that work together to provide accurate CO2 delivery to the planted aquarium. The needle valve allows precise tuning of CO2 flow rate, enabling the aquarist to adjust bubble count according to tank requirements. This is crucial, as even slight changes in flow rate can influence the overall water chemistry. The solenoid valve acts as an automated switch linked to a timer or lighting system, ensuring CO2 is injected only during specific periods. This helps avoid waste and reduces the risk of over-injection.

Another important component is the CO2 diffuser, which breaks CO2 into fine bubbles to increase dissolution efficiency in the water. The placement of the diffuser and the associated water flow can influence how evenly CO2 is distributed throughout the aquarium. Monitoring these conditions often requires the use of a drop checker, which displays approximate CO2 levels using color indicators. Together, these accessories form an integrated CO2 system that depends on the initial stability created by the regulator itself. The combination of these parts ensures that planted aquarium conditions remain sufficiently controlled to support the long-term health of aquarium vegetation.

Common Specifications and Performance Expectations

A typical aquarium pressure regulator includes specifications such as inlet pressure rating, working pressure range, and compatibility with various gas cylinder types. Because CO2 cylinders may vary in pressure depending on local temperature and filling standards, regulators must be designed to accommodate these variations safely. Working pressure specifications typically fall within ranges suitable for needle valve operation, ensuring smooth adjustments without sudden changes in flow. Additionally, many CO2 regulators include gauges that display both cylinder pressure and output pressure, allowing aquarists to monitor system performance at a glance. These monitoring elements enhance understanding of gas consumption and make it easier to anticipate cylinder replacement.

Some regulators are designed with integrated solenoid valves, while others require separate installation. Integrated designs help simplify the setup process and reduce the number of connection points, which can decrease the risk of leaks if the regulator is assembled properly. The choice between brass, stainless steel, or aluminum components can influence durability and resistance to corrosion. Because regulators operate under pressurized conditions, materials must be selected to ensure stability and longevity. Understanding these specifications helps aquarists choose a regulator that aligns with their aquarium size, CO2 demands, and long-term maintenance preferences.

Choosing the Right Aquarium Pressure Regulator

Selecting a regulator for a planted aquarium requires consideration of CO2 system design, tank size, plant density, and overall maintenance preference. A dual stage regulator is often selected for situations where pressure stability is a priority or where end-of-tank dump risks must be minimized. In contrast, a single stage regulator meets the needs of many hobbyists who manage small to medium tanks with moderate plant demands. Installation requirements must also be evaluated, including compatibility with local gas cylinder types and the need for adapters. Proper water measurement using a drop checker and consistent bubble count observation helps determine whether the regulator’s adjustments are suitable for the aquarium environment.

Once installed, aquarium pressure regulators require occasional inspection to ensure stable performance. Connections should be checked regularly, and the needle valve may require minor adjustments as plants grow and begin to consume more CO2. If irregularities in flow rate occur, aquarium keepers may need to review the regulator settings, inspect the solenoid valve, or evaluate the diffuser for clogging. These steps contribute to long-term CO2 stability and support healthy plant growth. Because the regulator forms the core of the CO2 system, choosing a reliable model simplifies maintenance and enhances control over the planted aquarium.

Maintenance Practices and Troubleshooting Considerations

Maintenance plays a significant role in ensuring that the aquarium pressure regulator continues to operate reliably. Routine checks involve examining all fittings for potential leaks and confirming that output pressure remains stable based on visual gauge readings. Over time, minor adjustments may be necessary due to gradual changes in cylinder pressure or variations in environmental temperature. A drop in CO2 flow rate can often be corrected by inspecting the needle valve or cleaning the diffuser. These maintenance habits help prevent unexpected CO2 fluctuations that could affect plant health.

Troubleshooting typically involves reviewing components such as solenoid valve operation, tubing integrity, and gauge accuracy. If the regulator shows inconsistent pressure, it may be related to worn internal parts or excessive debris accumulation within the system. Aquarists may also observe signs of end-of-tank dump in single stage regulators, which can be addressed by replacing the cylinder before pressure drops too low. When necessary, calibrating CO2 levels by adjusting the needle valve or observing changes in drop checker color can help bring conditions back into balance. With consistent care, the regulator remains a reliable part of the planted aquarium CO2 system.

Types of Aquarium Pressure Regulators

Understanding Single-Stage and Dual Stage Regulators

The aquarium pressure regulator is one of the most important devices in a CO2 system for a planted aquarium, providing controlled CO2 injection to maintain a stable environment for plant growth. Among the different types available, single stage regulators and dual stage regulators are commonly used due to their distinct structural characteristics and operational behavior. A single stage regulator reduces high cylinder pressure to working pressure in one step. This design is widely used in many aquarium setups because of its straightforward structure and accessibility. However, the pressure reduction in a single step may result in fluctuations when the cylinder pressure becomes low, which is often referred to as end-of-tank dump. These fluctuations can cause abrupt changes in CO2 output, and aquarists are encouraged to monitor bubble rate and drop checker readings more frequently when cylinder levels approach depletion.

A dual stage regulator, by comparison, reduces pressure in two controlled steps. The dual stage structure provides more consistent output pressure throughout the lifespan of the CO2 cylinder, making it a preferred choice for those seeking greater stability in CO2 injection. This design minimizes the risk of sudden increases in CO2 flow toward the end of the cylinder’s life, helping maintain more predictable conditions for both plants and aquatic animals. While dual stage regulators can be more complex and may involve a higher initial investment, many aquarists value their increased stability, especially in large planted aquarium setups where consistent CO2 delivery plays a significant role. The choice between single stage and dual stage regulator types typically depends on tank size, maintenance frequency, and the aquarist’s preference for precision versus simplicity.

Pros and Cons of Single-Stage and Dual Stage Regulators

Both single stage and dual stage regulators offer benefits and limitations, and understanding these characteristics can help aquarists choose the most suitable device for their CO2 system. Single stage regulators are commonly chosen for smaller aquariums due to their ease of installation and compatibility with basic planted aquarium setups. Users of single stage models often rely on needle valve adjustments and close monitoring of drop checker color to maintain stable CO2 levels. Although these regulators support effective CO2 injection in many situations, their working pressure may change as the gas cylinder becomes depleted, requiring more attention from the aquarist.

Dual stage regulators provide consistent output control due to their two-step pressure reduction system. This design helps reduce the chance of CO2 spikes, which can be critical for aquariums with sensitive plants or animals. Because dual stage regulators maintain stable output until the cylinder is nearly empty, they allow for more predictable CO2 delivery paired with steady bubble rate control. The tradeoff is that dual stage regulators can be more advanced, requiring a slightly more involved setup process. Nevertheless, their consistent performance makes them a common choice for large or heavily planted aquariums that require reliable CO2 injection.

Adjustable Versus Non-Adjustable Regulators

Aquarium pressure regulators can further be categorized as adjustable or non-adjustable depending on their capacity to modify working pressure. Adjustable regulators allow users to fine-tune the output pressure according to their CO2 system configuration, giving aquarists flexibility to adapt CO2 injection based on tank size, diffuser type, and overall flow rate requirements. This type of regulator is especially useful when paired with a precise needle valve, as the combination enables smooth adjustments to bubble count. Adjustable regulators are often selected by aquarists who prefer detailed control or who maintain aquariums with demanding plant species that rely on consistent CO2 levels.

Non-adjustable regulators operate based on a fixed working pressure predetermined by the manufacturer. These regulators provide a consistent and simplified CO2 output that is adequate for many standard planted aquariums. While they may not offer the same degree of customization as adjustable models, non-adjustable regulators reduce the likelihood of misconfiguration by limiting manual settings. This characteristic can be beneficial for beginners or those who prefer a straightforward CO2 injection process that requires minimal adjustment over time. The primary limitation is that fixed pressure designs may not pair optimally with every type of CO2 diffuser or high-demand planted aquarium, especially if specialized flow rates are required for optimal gas dissolution.

The Importance of Solenoid Valves in CO2 Regulators

Solenoid valves are essential components in many aquarium pressure regulator assemblies, providing automated control over CO2 injection. A solenoid valve is typically connected to a timer or lighting system so that CO2 flow automatically stops when the lights turn off. This is important because plants do not consume CO2 during the night, and allowing continuous CO2 injection after the photoperiod can cause unnecessary CO2 accumulation in the aquarium. Excess CO2 can affect fish and invertebrates, making the solenoid valve a practical safety measure that contributes to overall aquarium stability. With a solenoid valve integrated into the CO2 regulator or installed separately, aquarists can maintain precise CO2 schedules without requiring manual intervention.

In addition to convenience, solenoid valves help extend the lifespan of the CO2 cylinder by preventing waste during non-photosynthetic hours. This makes CO2 injection more efficient, especially in large planted aquariums that consume significant volumes of CO2 during the day. Solenoid valves also support consistent bubble rate management by preventing nighttime gas release that could interfere with daily CO2 calibration. When paired with a needle valve, diffuser, and drop checker, the solenoid valve forms part of an integrated CO2 system designed to maintain stability in the planted aquarium environment. Many modern aquarium pressure regulators include a built-in solenoid valve to simplify installation and reduce the number of connection points, though external versions remain available for aquarists who prefer modular configurations.

Comparing Solenoid-Integrated and Non-Integrated Regulators

Some aquarium pressure regulators are manufactured with solenoid valves built into the design. These integrated models offer convenience by reducing the need for additional equipment, making the CO2 system more compact and easier to assemble. With fewer components to connect, there is also a lower chance of leaks if the regulator is installed correctly. Solenoid-integrated regulators are often preferred by aquarists who value simplicity or who maintain multiple planted aquariums where compact configurations are beneficial.

Non-integrated regulators require a separate solenoid valve attachment. Although this adds an extra component to the CO2 system, it allows for greater flexibility in choosing solenoid valve specifications, materials, or replacement parts. Some aquarists prefer this approach because it enables swapping solenoid valves without replacing the entire pressure regulator. Both integrated and non-integrated models can function effectively when paired with the correct needle valve and CO2 diffuser setup. The decision between these types depends on whether convenience or modularity is prioritized in the overall CO2 injection strategy.

How to Choose the Right Pressure Regulator

Evaluating Aquarium Size and CO2 Demand

Choosing an aquarium pressure regulator requires an understanding of the aquarium’s size and its overall CO2 demand. In a planted aquarium, CO2 injection plays a central role in supporting photosynthesis, nutrient absorption, and stable plant development. Larger aquariums typically require higher CO2 output because a larger water volume dilutes dissolved CO2 more quickly, making consistent injection essential. Smaller aquariums, on the other hand, may only need moderate CO2 levels, and therefore the CO2 regulator can operate at lower working pressure and flow. The selection of a regulator should therefore begin by determining how much CO2 the aquarium will consume based on plant density, lighting intensity, and water movement.

In aquariums with dense vegetation or species known to rely heavily on CO2, maintaining a steady and reliable CO2 flow becomes particularly important. In such cases, a dual stage regulator may be preferable due to its stable output and reduced risk of pressure fluctuation as the cylinder becomes depleted. For smaller tanks or those with lower CO2 demand, a single stage regulator may be adequate as long as the aquarist monitors bubble rate changes using a drop checker and performs regular maintenance. Understanding these requirements allows aquarists to choose a regulator that matches their CO2 system’s operational expectations and supports long-term plant health.

Considering Budget and Key Functional Features

Budget is an essential factor when selecting a CO2 regulator, as different models come with varying features and construction quality. Entry-level regulators are often single stage designs and may include basic components such as gauges and a simple needle valve. These models are suitable for new hobbyists who want a functional CO2 system without significant investment. However, aquarists with medium to large planted aquariums may benefit from regulators with more advanced features, including dual stage pressure control, integrated solenoid valves, and more precise needle valves. While these models often come at a higher cost, they offer improved stability and reduced long-term maintenance.

Features such as gauge clarity, compatibility with standard CO2 cylinders, and availability of replacement parts also influence the selection process. A regulator with clear, readable gauges makes monitoring cylinder pressure and working pressure easier, reducing guesswork and improving daily CO2 calibration. Additionally, regulators that support both adjustable and non-adjustable working pressure options can cater to a variety of CO2 system configurations. Some CO2 regulators are designed with modular components, enabling users to upgrade elements like the solenoid valve or needle valve independently. These features provide flexibility and can extend the lifespan of the overall CO2 system.

The Importance of Needle Valves for Fine-Tuning CO2 Flow

The needle valve is one of the most important components of any aquarium pressure regulator. It controls the CO2 flow rate by adjusting the bubble count, allowing the aquarist to fine-tune CO2 injection based on plant needs and the aquarium’s CO2 consumption rate. A precise needle valve ensures small adjustments are possible, which is crucial for maintaining stable CO2 levels. Poorly constructed needle valves can make adjustments inconsistent, leading to fluctuating CO2 output that affects plant growth or stresses aquarium inhabitants.

A high-quality needle valve provides smooth and predictable control, especially when paired with a CO2 diffuser that requires stable pressure to dissolve CO2 efficiently. This combination helps produce uniform CO2 distribution throughout the planted aquarium. Many aquarists rely on a drop checker to observe long-term CO2 trends and to ensure adjustments made with the needle valve are producing the desired results. When selecting a CO2 regulator, confirming that the needle valve is well-constructed and capable of precise control should be a priority, as this contributes significantly to the accuracy of CO2 injection.

Safety Features and Their Importance

Safety plays an important role when choosing an aquarium pressure regulator. Since pressurized CO2 cylinders contain gas under high pressure, the regulator must include certain safety features to ensure safe operation within the planted aquarium environment. One important feature is an over-pressure relief valve, which prevents the buildup of excessive internal pressure that could otherwise damage equipment or cause unexpected CO2 release. This valve automatically vents excess pressure, maintaining the CO2 system's stability and reducing potential risks.

In addition to over-pressure protection, regulators should be designed from durable materials capable of handling long-term exposure to pressurized gas. Brass and stainless steel components are commonly used due to their corrosion resistance and structural stability. Some regulators also include reinforced seals or washers that help prevent leaks at critical connection points. Leak-free operation is essential for maintaining consistent CO2 injection and safe operation. Aquarists should also confirm compatibility between the regulator and the CO2 cylinder valve type to ensure proper installation.

Examining Solenoid Valve Features for Automated Control

A solenoid valve is an optional but highly useful addition to an aquarium pressure regulator. It automates CO2 injection by turning the flow on and off using a timer or lighting controller. Since plants do not consume CO2 during the night, using a solenoid valve prevents unnecessary injection during dark hours. This reduces CO2 waste while helping shield aquarium inhabitants from excessive nighttime CO2 levels. Choosing a regulator with an integrated solenoid valve can simplify installation, reduce the number of connections, and lower the chance of gas leakage.

Standalone solenoid valves offer flexibility, especially for aquarists who prefer modular CO2 system configurations. These can be replaced independently without removing the entire regulator assembly. When selecting a solenoid valve, factors such as heat output, noise level, and connection compatibility should be considered. A well-designed solenoid valve contributes greatly to the overall stability of the CO2 system by ensuring consistent, timed CO2 injection aligned with the planted aquarium’s photoperiod.

Additional Factors to Guide Regulator Selection

Other considerations may influence the choice of an aquarium pressure regulator. The type of CO2 cylinder used, whether disposable cartridges or standard refillable cylinders, must match the regulator threading and sealing system. The regulator should also provide clear indicators through its gauges so the aquarist can track both cylinder pressure and output pressure effectively. This information helps determine when the CO2 system requires refilling and whether adjustments to the needle valve are needed to maintain proper CO2 injection levels.

The availability of spare parts and maintenance support can also be important for long-term use. Regulators with common thread types, standard fittings, and replaceable seals are easier to maintain and service if issues arise. For aquarists who maintain multiple planted aquarium setups, selecting a regulator with consistent performance and uncomplicated maintenance reduces the time spent adjusting CO2 system components. By taking all these factors into account, aquarists can select a CO2 regulator that meets the needs of their aquarium, supports consistent CO2 injection, and integrates well with accessories such as the needle valve, CO2 diffuser, and drop checker.

Setting Up Your Aquarium Pressure Regulator

Connecting the Aquarium Pressure Regulator to the CO2 Tank

The process of setting up an aquarium pressure regulator involves understanding how the components of a CO2 system work together to support the needs of a planted aquarium. An aquarium pressure regulator, often referred to as a CO2 regulator, is the device responsible for reducing the high pressure inside a CO2 cylinder to a controlled and stable working pressure suitable for CO2 injection. Proper installation is important to ensure consistent flow and to protect the other components, including the needle valve, solenoid valve, CO2 diffuser, and associated tubing. To begin the installation, the CO2 tank must be placed on a stable and upright surface, ensuring that the valve area is easily accessible. Before attaching the CO2 regulator, it is recommended to briefly release a small burst of gas from the tank valve to clear any dust or particles. The regulator can then be aligned with the tank’s valve thread and tightened securely by hand or with an appropriate wrench, ensuring no cross-threading occurs. This step ensures a stable foundation for the rest of the CO2 system and supports safe CO2 injection throughout the operation of the planted aquarium.

Connecting Supporting Components in the CO2 System

Once the aquarium pressure regulator or CO2 regulator is mounted on the tank, other components must be connected to complete the CO2 system. The solenoid valve, if included as part of the assembly, enables automated control and allows the CO2 injection to run only during the lighting period. Some CO2 regulators come with a built-in solenoid valve, while others require it to be attached externally. After confirming that the solenoid valve is properly integrated, the needle valve must be positioned to allow fine adjustments of the CO2 flow rate. The outlet of the needle valve is then connected to CO2-resistant tubing, ensuring that the selected tubing materials are compatible with long-term CO2 exposure. The tubing should run from the regulator to the CO2 diffuser placed inside the planted aquarium. This diffuser transforms pressurized gas into fine CO2 bubbles, increasing the efficiency of CO2 dissolution in the water. A drop checker can also be introduced into the system to monitor CO2 concentration and confirm that the regulator settings consistently support healthy plant growth.

Adjusting the Working Pressure for Stable CO2 Injection

After assembling the components, the next step is adjusting the working pressure of the aquarium pressure regulator. The working pressure represents the amount of pressure delivered to the needle valve, and it plays an important role in maintaining consistent flow through the CO2 diffuser. Different CO2 diffusers may require different working pressures, so reviewing the water flow characteristics and the diffuser specifications is beneficial. By turning the working pressure adjustment knob on the CO2 regulator, the output pressure can be gradually set. Maintaining a stable working pressure supports predictable CO2 injection and helps the planted aquarium maintain steady conditions throughout the day. Monitoring the gauge readings is helpful, as the gauge on most CO2 regulators clearly displays both cylinder pressure and working pressure. Ensuring appropriate values reduces fluctuations and supports a more stable environment for plant photosynthesis.

Setting and Fine-Tuning the Bubble Count

The bubble count represents the visible rate of CO2 entering the planted aquarium through the diffuser, and it must be adjusted to match the tank’s CO2 demand. Using the needle valve, aquarists can slowly open or close the gas flow to reach the desired bubble count. This part of the CO2 system is sensitive, and the needle valve must be adjusted with small, deliberate movements. Observing the bubble counter helps determine if the CO2 regulator and needle valve are providing uniform output. Once the bubble count stabilizes, the planted aquarium begins receiving consistent CO2 injection. Adjustments may be necessary over several hours or days to reach the appropriate level, especially in tanks with high plant density or strong lighting. Maintaining a consistent bubble rate supports steady CO2 levels and contributes to balanced water parameters.

Calibrating the System Using a Drop Checker

Calibrating the CO2 system is a key part of setting up the aquarium pressure regulator, as it confirms that the CO2 regulator and needle valve are supplying the correct amount of CO2. A drop checker is used for this purpose, providing a simple visual reference for CO2 concentration. The drop checker contains an indicator solution that changes color based on the amount of dissolved CO2 in the water. After installing the CO2 system and setting the initial bubble count, the drop checker should be placed in an area of the tank with good water circulation. Over the next few hours, the color will indicate whether adjustments to the CO2 regulator are needed. A green color typically suggests that the CO2 level is appropriate for most planted aquariums. If the indicator appears blue, the CO2 injection may be too low, requiring fine adjustments to the needle valve. If the indicator leans toward yellow, the CO2 concentration may be too high, and reducing flow through the needle valve may be necessary. Using the drop checker ensures that CO2 injection remains within a range that supports plant health without causing stress to aquatic life.

Key Components and Their Functions in a CO2 System

Maintaining Safe and Stable Operation After Setup

After completing the installation, it is beneficial to periodically check all components in the CO2 system to ensure safe operation. The aquarium pressure regulator should be examined for leaks, and tubing should remain securely attached. Monitoring gauge readings helps detect early changes in CO2 cylinder pressure, which may affect the stability of CO2 injection in the planted aquarium. During routine water changes or maintenance, verifying that the needle valve and solenoid valve continue to function as intended supports long-term reliability. These steps help maintain stable CO2 injection and contribute to creating an environment that supports plant health and growth without large fluctuations in CO2 levels.