Just like terrestrial plants, aquatic plants need CO2, or carbon dioxide, for growth and function. Low level plants, like mosses, Java ferns, and even algae all need very little CO2. Usually, low CO2 utilizers are able to access the CO2 that fish and invertebrates release with respiration. In fact, many aquatic plants will survive without added CO2, but they won’t thrive.

CO2 injection in aquariums often brings out the best colors and fastest growth, especially when combined with appropriate light. Choosing a CO2 system can be confusing and complicated, and there are multiple parts that go into a CO2 injection system. One of the key pieces is a CO2 regulator, which allows you to control how much CO2 enters your aquarium and how quickly.

These reviews of the 7 best aquarium CO2 regulators are intended to help you navigate through these products without leaving you feeling overwhelmed. These products come in a range from basic to bells and whistles, so there’s something here for everyone’s comfort and skill level.divider1- goldfish

A Quick Comparison of Our Favorites

Image Product Details
Best Overall
Winner
FZONE Aquarium CO2 Regulator DC Solenoid FZONE Aquarium CO2 Regulator DC Solenoid
  • Cost-effective
  • Sturdy aluminum alloy
  • Includes tools for installation
  • Best Value
    Second place
    VIVOSUN CO2 Regulator Emitter System VIVOSUN CO2 Regulator Emitter System
  • Best value
  • Industrial solenoid valve
  • Made with sturdy brass components
  • Premium Choice
    Third place
    FZONE Pro Series Aquarium Dual Stage CO2 Regulator FZONE Pro Series Aquarium Dual Stage CO2 Regulator
  • Uses 12V DC solenoid
  • Sturdy aluminum construction
  • Adjustable output pressure to prevent CO2 dumping
  • KIPA CO2 Regulator with Solenoid Valve KIPA CO2 Regulator with Solenoid Valve
  • Cost-effective
  • Four purchasing options
  • Made from strong copper
  • YaeTek CO2 Regulator Aquarium Mini YaeTek CO2 Regulator Aquarium Mini
  • Cost-effective
  • Diffuses fine CO2 bubbles
  • Includes installation tools
  • The 7 Best Aquarium CO2 Regulators – Reviews 2021

    1. FZONE Aquarium Co2 Regulator DC Solenoid– Best Overall1FZONE Aquarium Co2 Regulator DC Solenoid

     

    The FZONE Aquarium CO2 Regulator DC Solenoid is the best overall pick for aquarium CO2 regulators. It has an updated split-type DC solenoid, making it safer and more stable. It’s made of sturdy aluminum alloy.

    This product has dual gauges that measure 1.6 inches in diameter, making them easy to read and use. It features high precision fine-tuning that allows for easy CO2 regulation for your aquarium. It includes a bubble counter and check valve, outlet pressure gauge, cylinder inner pressure gauge, and a precision fine-tuning valve that allows for a rate as slow as 1 bubble per 5 seconds. It also includes the tools you need for installation. It has a no-noise guarantee, so it shouldn’t produce distracting noise, and has a cool operating temperature.

    The solenoid valve on this product does tend to continue to release CO2 for 1 hour or more after being shut off. This regulator does not include very clear instructions, so you may have to reach out to the manufacturer for clear setup instructions.

    Pros
    • Cost-effective
    • Updated split-type DC solenoid
    • Sturdy aluminum alloy
    • Large dual gauges are easy to read and use
    • High-precision fine-tuning
    • Includes bubble counter, check valve, pressure gauges, and fine-tuning valve
    • Includes tools for installation
    • No-noise guarantee
    • Cool operation
    Cons
    • No storage space

    2. VIVOSUN CO2 Regulator Emitter System – Best Value2VIVOSUN Hydroponics CO2 Regulator Emitter System

     

    The best aquarium CO2 regulator for the money is the VIVOSUN CO2 Regulator Emitter System. It includes an industrial solenoid valve and is made with sturdy brass components.

    This product has a single pressure gauge that is just over 1.5 inches in diameter and is built into the body of the regulator. It also has a flow meter that is adjusted by the simple turn of a knob. It includes a 3-prong plug, just over 16 feet of black plastic dispensing tubing, and two plastic washers. The solenoid is compatible with timers, allowing you to have a hands-off approach once set.

    You may need to apply Teflon tape to the threads of the tubing before use to ensure there is a tight connection and CO2 does not leak. The CO2 bubble rate of this regulator is not super precise, so close monitoring is necessary.

    Pros
    • Best value
    • Industrial solenoid valve
    • Made with sturdy brass components
    • Single large pressure gauge is easy to read
    • Flow meter is easy to adjust with knob turn
    • Comes with over 16 feet of dispensing tubing and plastic washers for installation
    • Solenoid is compatible with timers
    Cons
    • Will likely leak without Teflon tape added to connection threads
    • Not very precise

    3. FZONE Pro Series Aquarium Dual Stage CO2 Regulator– Premium Choice3FZONE Pro Series Aquarium Dual Stage

     

    The premium choice for aquarium CO2 regulators is the FZONE Pro Series Aquarium Dual Stage CO2 Regulator. This product uses a 12V DC solenoid, so it is stable and uses less energy than the old school AV solenoids. This product is made from sturdy aluminum.

    This CO2 regulator features two manifold blocks that both come with high-precision needle valves that can be operated independently of each other. This allows you to use this regulator for one or two separate aquariums. It has an adjustable output pressure from 0-65 PSI, preventing CO2 dumps and other unexpected complications. This product has a built-in safety valve that will automatically open once PSI exceeds 100 and the CO2 output can be set as low as a bubble every 3 seconds. It includes high- and low-pressure gauges, a sealing ring, bubble counter, and easy-to-use needle valves and pressure adjusting knob.

    CO2 may continue being released for upwards of an hour after regulator shut off and may only stop if the canister is shut off.

    Pros
    • Uses 12V DC solenoid
    • Sturdy aluminum construction
    • Two manifold blocks that can be set separately and used for two tanks
    • Adjustable output pressure to prevent CO2 dumping
    • Built-in safety valve opens if PSI exceeds 100
    • CO2 output can be set as low as a bubble every 3 seconds
    • Includes high- and low-pressure gauges
    • High-precision needle valves and pressure adjuster are easy to use
    • Includes tools for installation
    Cons
    • Premium price
    • CO2 may continue being released upwards of an hour after shut off

    4. KIPA CO2 Regulator with Solenoid Valve4KIPA CO2 Regulator with Solenoid Valve and Flow-Meter Emitter

     

    The KIPA CO2 Regulator with Solenoid Valve is a cost-effective product that can be purchased as the regulator with solenoid and hose, regulator, regulator and hose, or just the hose. This product is made from strong copper.

    This product features a simple flow meter, easy to use pressure gauge, and AC solenoid. The most cost-effective way to purchase this product includes the regulator, solenoid, hose, and 3-prong plug. The flow meter can be set from 0-25 liters per minute. This product is easy to set up and does not require special tools for installation.

    To ensure this regulator does not allow CO2 leaks, it should be installed with Teflon tape on the threads to ensure there is a secure connection. This product may continue releasing CO2 after being unplugged for some time.

    Pros
    • Cost-effective
    • Four purchasing options
    • Made from strong copper
    • Includes easy to use flow meter and pressure gauge
    • Can be set up to 25 L/min
    • Easy to set up
    • No special tools needed for installation
    Cons
    • Will likely leak without Teflon tape added to connection threads
    • May continue to release CO2 after being unplugged
    • Uses an AC solenoid which is less energy efficient than a DC solenoid

    5. YaeTek CO2 Regulator Aquarium Mini5YaeTek CO2 Regulator Aquarium Mini Stainless Steel

     

    The YaeTek CO2 Regulator Aquarium Mini is compatible with most brands of high-density CO2 injection tubing. It uses a 110V AC solenoid and is cost-effective.

    This product is compatible with most CO2 atomizer and diffuser brands. YaeTek’s goal with this product was to create a CO2 regulator that conveniently works with the setup or products you already have. This CO2 regulator includes a bubble counter with a high-quality high pressure check valve, large dual pressure gauge, and installation tools. This diffuses fine CO2 bubbles, allowing for more diffuse distribution of CO2 into the water.

    This product is cost-effective but is not built to last and will likely require a replacement within a year or so. This product will continue to release CO2 for some time after being unplugged.

    Pros
    • Cost-effective
    • Compatible with most brands of CO2 atomizers and diffusers
    • Conveniently works with setup you already have
    • Includes bubble counter, check valve, and dual pressure gauge
    • Includes installation tools
    • Diffuses fine CO2 bubbles
    Cons
    • Not built to last and may need replacement within a year
    • May continue to release CO2 after being unplugged
    • Uses an AC solenoid which is less energy efficient than a DC solenoid

    6. AQUATEK CO2 Regulator6Basic AQUATEK CO2 Regulator with Cool Touch Solenoid

     

    The AQUATEK CO2 Regulator has an industrial solenoid that stays cool to the touch. This product is made from durable brass and is made to last a long time.

    This CO2 regulator is compatible with most brands of CO2 atomizers, diffusers, and high-density tubing. It includes a bubble counter, dual gauges, integrated check valve, and precision needle valve. The precision valve allows for fine-tuning the release of CO2 into your tank.  One of the dual gauges shows the CO2 tank capacity while the other shows the output pressure.

    This product will continue to release CO2 after shut off while CO2 bleeds from the tubing. The solenoid may become clogged with dirt particles from the CO2 tank, so it may need to be disassembled and cleaned with canned air from time to time. This regulator may need Teflon tape on the connection threads to prevent leaks. The needle valve is sensitive and may take practice and adjustments to set correctly.

    Pros
    • Industrial solenoid
    • Cool to the touch
    • Made from durable brass
    • Compatible with most brands of CO2 atomizers, diffusers, and tubing
    • Includes bubble counter, dual gauges, check valve, and needle valve
    • Precision valve allows for fine-tuning of CO2 release
    • Dual gauges show tank capacity and output pressure
    Cons
    • May continue to release CO2 from the tubing after shut off
    • Solenoid may need to be disassembled for cleaning routinely
    • Will likely leak without Teflon tape added to connection threads
    • Needle valve may take practice and adjustments for proper settings

    7. CO2 Art Pro-Elite Series Dual Stage CO2 Regulator7CO2 Art Pro-Elite Series The Most Advanced Aquarium

     

    The CO2 Art Pro-Elite Series Dual Stage CO2 Regulator has a 12V DC solenoid and can be used for tanks as small as 2 gallons and as large as 1000 gallons. It is made from stainless steel.

    This CO2 regulator is made for safety and high-precision in mind. The dual stage construction ensures CO2 dumping at the end of a tank does not occur. It features high-precision needle valve, bubble counter, dual gauges, and extendable manifold block that allows you to add or remove blocks to suit your needs. One of the dual gauges shows tank volume and flow pressure while the other shows working pressure.

    This product is the most premium-priced product of the reviewed items. The fine-tuning needle valve may take time to get set correctly and since it is high-precision, may be sensitive. This regulator may continue to release CO2 as it bleeds from the tubing after being turned off.

    Pros
    • 12V DC solenoid
    • Made for tanks from 2-1000 gallons
    • Includes needle valve, bubble counter, and dual gauges
    • Dual gauges show tank volume, flow pressure, and working pressure
    • Extendable manifold block allows for customization based on needs
    Cons
    • Premium price
    • May continue to release CO2 from the tubing after shut off
    • Needle valve may take practice and adjustments for proper settings

    Buyer’s Guide

    Terms You Need to Know Regarding CO2 Regulators:

    • Solenoid: A solenoid is a wire coil that is used as an electromagnet to create mechanical energy from electrical energy, powering the device.
    • Gauge: A round display that shows you either the set pressure or working pressure of the regulator.
    • Bubble Counter: This simple device allows you a visual of how much CO2 is being released into your aquarium at a rate of a bubble for every X seconds.
    • Needle Valve: This valve allows for high precision of the output of CO2 via a narrow valve with a port and needle-shaped plunger piece.
    • Check Valve: A check valve is a type of valve that allows for one-way flow. This prevents backflow from the aquarium into the CO2 system.
    • Manifold Valve: This item helps allow for pressure control and in some cases, multiple manifold blocks can be connected to allow for pressurized output to multiple locations.
    What to Consider When Choosing a CO2 Regulator for Your Aquarium:
    • Your Budget: CO2 regulators and injection systems can range anywhere from tens to hundreds of dollars. Determining your comfortable budget prior to setting up a system will help you pick a product. The last thing you want to do is accidentally spend your entire budget on one piece of a system without being able to use it.
    • Your Tank Size: The more precise control you have over CO2 output, the wider range of tanks you will likely be able to service. If your tank is only 10 gallons, then you’ll want to choose a CO2 regulator that allows for appropriate control of the CO2 output for a tank that size. Some regulators can work for tanks up to the hundreds or even thousands of gallons but may not be appropriate for smaller tanks.
    • Number of Tanks: How many tanks do you need to run CO2 into? If you have two or more tanks you want to run a CO2 system into, then choosing a product with a customizable number of manifold blocks may benefit you significantly, even though it will likely require a higher budget. Some CO2 regulators are only going to work for one tank and won’t be functional for you to use on multiple aquariums.
    • Available Space: Not only does the size of your tank matter, but the size of your available space for a CO2 system. Some regulators are compact without losing functionality or accuracy, while other regulators are large and bulky. If you want to be able to hide your CO2 system, then you may choose a smaller CO2 regulator.
    • Safety and Convenience: CO2 regulators come in a broad array of user levels, so finding one that you are comfortable using is possible, even if you’re a beginner to using a system like this. The most important part of a CO2 regulator is that you can operate it in a way that is safe for you and your aquarium. Some regulators have very sensitive knobs and gauges that may require more time to set and more thorough monitoring of the regulator’s function. Some regulators are more complex to use than others and some will allow for little to no effort when it comes to setup. Each type of product has its own pros and cons, so you’ll have to identify what you’re comfortable with and go from there.
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    Conclusion

    Did these reviews help you pick a product to get your CO2 injection system up and running? The best overall product is the FZONE Aquarium CO2 Regulator DC Solenoid for its user-friendly design and functionality. If you’re looking for a good deal, then the VIVOSUN CO2 Regulator Emitter System is the best value CO2 regulator. For a premium product, then the best pick is the FZONE Pro Series Aquarium Dual Stage CO2 Regulator, which carries efficient functionality and design at a premium price.

    Use these reviews to help you pick a product that will work best for you and your aquatic plants. Regardless of what product you choose, make sure to read up on setting up, operating, and maintaining a CO2 injection system. This will keep you and your aquatic life safe and give you a more beautiful, planted tank than you may have thought possible.

    Your red plants will develop eye-catching color, your green plants will look lush, and your fish and invertebrates will thank you for making their environment such an enriching, exciting place.


    Featured image credit: Solarisys, Shutterstock