6 Best Aquarium CO2 Diffusers 2020 – Reviews & Top Picks

Last Updated: October 10, 2020

AQUATEK 3-in-1 CO2 Diffuser inside aquariumCarbon dioxide (CO2) is one of the most critical nutrients for the plants in your aquarium. In its purest form, carbon dioxide is a gas. However, much like oxygen, it can be easily dissolved in water. Aquatic plants use dissolved CO2 to photosynthesize in a similar manner that regular garden variety plants would.

It’s worth noting that freshwater aquatic plants take in CO2 and expel oxygen throughout the tank water. They need more CO2 to flourish as to what is already derivable in your freshwater tank.

This is where an aquarium CO2 diffuser comes into play. A CO2 diffuser utilizes reactors or membranes to efficiently dissolve droplets of gaseous CO2 directly into the water inside of the aquarium, creating an ideal environment for your underwater plants to thrive.

There are many different aquarium CO2 diffusers available on the market. But which one is best for you? In this article, we’ll explore the top six best CO2 diffusers of 2020 reviews and offer you a comprehensive buying guide in order to find the right one for your aquatic landscape. Here are our top picks for the best aquarium CO2 diffusers of 2020.

A Quick Comparison of Our Favorites

Image Product Details
Best Overall
Winner
Fluval Fluval
  • Easy to install
  • Affordable
  • Plastic body will not easily break
  • Best Value
    Second place
    Rhinox Nano Rhinox Nano
  • High-quality material
  • Slows water down
  • Aesthetically pleasing
  • Premium Choice
    Third place
    NilocG Aquatics Atomic Inline NilocG Aquatics Atomic Inline
  • Can be installed directly below or into the tank
  • Hard to break
  • Easy to clean
  • JARDLI Pollen Glass JARDLI Pollen Glass
  • Built-in bubble counter
  • Can fit a number of tank sizes
  • Adjustable
  • Aquario Neo CO2 Diffuser Aquario Neo CO2 Diffuser
  • Eye-pleasing clear acrylic
  • Works with a DIY system
  • Sturdy
  • The 6 Best Aquarium CO2 Diffusers – Reviews 2020

    1. Fluval CO2 Ceramic Diffuser – Best Overall

    Fluval CO2 Ceramic Diffuser

    This ceramic CO2 diffuser boasts a simple design and sturdy, rounded plastic construction. Resembling a tiny black tire, the Fluval CO2 Ceramic Diffuser has a small nipple coming out of the top where you attach your CO2 line. The entire thing can be seamlessly attached to the side of your tank with a suction cup. It’s super simple to install and will not easily break. It’s also extremely affordable, so if you have a few tanks, you can easily buy one for each of them.

    It’s kind of an eyesore but luckily the small design makes it easy to hide it behind your fish tank plants. It also does not work well in big tanks and cannot be taken apart for cleaning purposes.

    Pros
    • Plastic body will not easily break
    • Easy to install
    • Affordable
    Cons
    • Ugly
    • Doesn’t work in big tanks
    • Can’t be taken apart to clean

    2. Rhinox Nano CO2 Diffuser – Best Value

    Rhinox Nano CO2 Diffuser

    The Rhinox Nano CO2 Diffuser is certainly the best aquarium CO2 diffuser for the only. Costing less than $16, this aesthetically appealing CO2 diffuser looks great in any fish tank and is really easy to assemble and install. Rhino uses innovative technology and high-grade material for maximum performance. Moreover, the product’s cylinder shape helps to slow down the speed of your water so your plants can make the most of it.

    The one drawback of this diffuser is that it works best in tanks 20 gallons and under. Some buyers have also complained that this diffuser is a tad noisy too.

    Pros
    • Affordable
    • Aesthetically pleasing
    • High-quality material
    • Slows water down
    Cons
    • Made for smaller tanks
    • Noisy

    3. NilocG Aquatics Atomic Inline CO2 Atomizer Diffuser – Premium Choice

    NilocG Aquatics Atomic Inline CO2 Atomizer Diffuser

    Available in an array of sizes to fit any freshwater tank, the NilocG Aquatics Atomic Inline CO2 Atomizer Diffuser is our premium choice CO2 diffuser pick. It’s a breeze to install and can be mounted below or directly to the tank. Producing an ultra-fine mist with an average bubble diameter of less than 0.1mm, this diffuser is easy to clean with a water/bleach solution and is tough to break.

    It is on the pricey side of the spectrum. Additionally, when the solenoid cuts off, the product wills with water and sometimes fails. It’s also less pleasing to look at than other CO2 diffusers.

    Pros
    • Easy to install
    • Easy to clean
    • Can be installed directly below or into the tank
    • Hard to break
    Cons
    • Expensive
    • Can fail if solenoid cuts off
    • Not visually appealing

    4. JARDLI Pollen Glass CO2 Diffuser

    JARDLI Pollen Glass CO2 Diffuser

    The JARDLI Pollen Glass CO2 Diffuser is a bell-shaped CO2 diffuser that has a built-in bubble counter. Water fills the bell in between the ceramic disk and tube. As the gas exits the tube, it will go through the diffuser’s fine points and creates a bubble. This eliminates the need for separate bubble counterparts. The height is adjustable, allowing it to easily fit in a large number of tank sizes.

    It is made completely of glass, making it pretty to look at, but fragile. Additionally, you cannot remove the ceramic disk to clean it or replace it, and the kit doesn’t include a check valve or U-bend.

    Pros
    • Built-in bubble counter
    • Adjustable
    • Can fit a number of tank sizes
    Cons
    • Fragile
    • Cannot remove or replace the ceramic disk
    • No U-bend or check valve

    5. Aquario Neo CO2 Diffuser

    Aquario Neo CO2 Diffuser

    This specific aquarium CO2 diffuser is unique to our list because it works with a DIY system. The highly-porous membrane will bubble even in low-pressure fish tanks. Made from a highly resilient clear acrylic, it has all the beauty of a glass diffuser but is a lot stronger. It also comes in small and medium sizes, making it perfect for smaller sized tanks.

    The ceramic disk does not come off, so you cannot remove it to clean it or replace it. It also does not come with a check valve, U-bend, or bubble checker.

    Pros
    • Eye-pleasing clear acrylic
    • Sturdy
    • Works with a DIY system
    • Available in small and medium sizes
    Cons
    • Ceramic disk does not come off
    • Does not come with a U-bend, bubble checker, or a check valve

    6. AQUATEK 3-in-1 CO2 Diffuser

    AQUATEK 3-in-1 CO2 Diffuser

    The AQUATEK 3-in-1 CO2 diffuser is a compact and versatile aquarium CO2 diffuser that includes a diffuser, check valve, and bubble counter. Made from extra-fine ceramic, it provides an accurate measure of the flow rate while its check valve protects the air pump equipment and gas system from back-siphoning damage. It also will not flood if you lose power. It’s extremely affordable and offers more bang for your buck as it’s a three-in-one product.

    Some users have reported that the CO2 was not being diffused properly by this product and bubbles were escaping from the inner silicone gasket circle and ceramic disk.

    Pros
    • 3-in-1 product
    • Made from sturdy ceramic
    • Won’t flood if power is lost
    • Affordable
    Cons
    • CO2 can sometimes not be diffused correctly
    • Bubbles can escape

    Buyer’s Guide

    Devices and equipment for your aquarium can add up quickly. This is why it is wise to give your purchases some careful consideration before you buy. You want to ensure the aquarium CO2 diffuser matches your unique needs and style, and also optimally fits your tank size.

    There are several things you should think about when choosing an aquarium CO2 diffuser, such as the materials it’s crafted from, the ease of use, the look of it, and its compatibility with your fish tank.

    1. Materials It’s Crafted from: The first thing to think about when you’re on the hunt for the perfect aquarium CO2 diffuser is the materials it is made from. Typically, most aquarium CO2 diffusers are made from glass or stainless steel materials. When made from glass, it is more pleasing to the eye as it has a mirror-like appearance when placed in the water. However, glass aquarium CO2 diffusers are a lot more fragile than stainless steel ones.

    *However, stainless steel aquarium CO2 diffusers can look pretty ugly in your tank. But these types of models won’t break as easily as glass ones.

    2. Convenience and Ease of Usage: The second point of consideration when shopping for an aquarium CO2 diffuser is if it’s easy to install, take apart, and clean. Diffusers that come with ceramic discs are a lot easier to maintain because they only need a water/bleaching combination to clean them thoroughly.

    *Some other models require the disc to be changed after a particular length of time. While it can be pricey, it doesn’t have the hassle of maintenance as a replacement ceramic disc doesn’t require any cleaning at all.

    3. How Compatible Is It with Your Fish Tank: It’s critical to inspect the aquarium CO2 diffuser’s compatibility with your fish tank’s size. Many aquarium CO2 diffusers are available in different sizes to cater to the tank size. You can figure out what size you need by the size of the diffuser’s ceramic disc.

    *A general rule of thumb is that the smaller the ceramic disc is, the smaller the surface area for dispersing the CO2 bubbles needs to be. Thus, you will need to put it in a smaller tank size.

    Aquarium CO2 diffusers that come with discs with a diameter size of two inches or bigger are recommended for large tank sizes, normally 70 gallons of water or bigger.

    Aquarium CO2 Diffuser Frequently Asked Questions

    How does an aquarium CO2 diffuser work? Your aquarium CO2 diffuser works by breaking down large bubbles into smaller ones to be dispensed throughout the aquarium. This will increase the carbon dioxide levels in the water of your fish tank.

    How do I care for the diffuser? Aquarium CO2 diffusers are generally easy to care for, use, and operate. However, glass versions must be handled with care because they can break easily.

    When it comes to cleaning the device, use a solution of water and bleach, and soak the product in clean water for 24 hours after. When storing your aquarium CO2 diffuser, keep it in a dry and cool area and away from children to prevent damaging it.

    Are there different types of aquarium CO2 diffusers? Yes. There are a couple different types, including:

    • CO2 Reactor: This is generally the most expensive type of aquarium CO2 diffuser and produces the largest output of CO2. It’s better for larger fish tanks.
    • Ceramic Glass CO2 Diffuser: This kind of aquarium CO2 diffuser is fully submerged in the water and attaches to the tank glass with a sturdy suction cup. It’s a lot more affordable than a CO2 reactor and produces small and light bubbles.
    • In-line CO2 Diffuser: This type of aquarium CO2 diffuser is helpful for larger fish tanks that contain a lot of gallons of water. It is highly effective and safe to use.
    • Airstone Diffuser: We don’t recommend buying this type of diffuser. It makes large CO2 bubbles and this makes it tough for the carbon dioxide to spread evenly throughout the fish tank.
    • Ladder CO2 Diffuser: This one is made for smaller-sized fish tanks. Its name comes from its ladder-like shape.
    JARDLI Pollen Glass CO2 Diffuser inside aquarium
    Image: JARDLI Pollen Glass CO2 Diffuser, Amazon

    Benefits of Aquarium CO2 Diffusers

    Your aquarium CO2 diffuser plays a vital role in the health of the aquatic plants growing inside of your aquarium. They use the CO2 bubbles the diffuser makes as their primary source of carbon.

    Some of the perks of using an aquarium CO2 diffuser include:

    • Healthy, thriving plants in your tank
    • An affordable device that results in large, lush aquatic plants
    • Works for mostly all kinds of plants
    • Easy to use and operate

    divider-fishConclusion

    When all of the aquarium CO2 diffusers reviews are laid out on the line, the best one overall is the Fluval CO2 Ceramic Diffuser. It’s affordable, easy to install, and very durable. The best in value in our option is the Rhinox Nano CO2 Diffuser because it looks great in any tank, super affordable, and made from high-quality materials. It also slows the bubbles down so that your plants can get the most out of its use.

    When you’re on the hunt for an aquarium CO2 diffuser, ensure that it properly fits your tank. You can do this by looking at the size of the ceramic disk.

    For lush and gorgeous aquatic plants inside your fish tank, it’s important to utilize an aquarium CO2 diffuser to help them get the carbon they need to flourish.


    Featured Image: AQUATEK 3-in-1 CO2 Diffuser, Amazon