Best CO2 Systems for Planted Aquariums

Posted by on 01/26/2024

If you're deciding on a CO2 system for your aquarium, you might be a bit overwhelmed by all of the options on the market. Injecting CO2 into an aquarium can result in robust plant growth, and hobbyists will want to consider all of their options before making a purchase.

In this post, we're going to discuss the different types of CO2 systems you can use to make your planted aquarium flourish.


First on our list is the DIY (do it yourself) CO2 setup. This is the most budget-friendly option, as you're creating your CO2 system at home with items commonly found in most households. We won't get into the specifics, but essentially you fill an empty plastic bottle with warm water, sugar, cold water, and yeast. You cut a small hole in the top, attach some airline tubing, and connect the tubing to a CO2 diffuser placed inside of your tank.

As the yeast metabolizes the sugar, it will produce CO2. You won't be introducing CO2 as fast as a dedicated system, but it's a great cost-effective option for those looking to spruce up their aquarium plants, especially if it's your first time with CO2.

Disposable CO2

Disposable CO2 systems are just what you might have imagined. They are small-sized canisters that are safe to ship, and once the CO2 is used up, they can be discarded.

Fluval makes a popular CO2 kit and also sells disposable CO2 cartridges, which last about a month each.

While the small size and portability of these kits may attract newcomers, the cost can add up quickly, as hobbyists will need a steady supply of CO2 to keep their plants in tip-top shape throughout the year. We like this CO2 system in tiny aquariums (think 2.5 gallons.)

Paintball CO2

Next up is the Paintball CO2 system. As you may have guessed, this CO2 setup uses a CO2 tank that's used for a paintball gun. US-based hobbyists can purchase these CO2 tanks at Paintball shops, or even large sporting goods stores like Dick's Sporting Goods (which will also refill these paintball tanks at some locations.)

You'll also need to purchase a CO2 regulator that's sized for a paintball canister. A quick Google search should provide you with quite a few paintball-compatible regulators. We like this option for smaller tanks, such as those in the 5-10 gallon range.

Canister CO2

The Canister CO2 setup is the most used setup by experienced planted tank hobbyists. Most hobbyists will either go with a 5lb or 10lb CO2 tank, as well as an appropriately sized regulator to inject CO2 through a diffuser into their aquariums.

While the upfront cost of buying a CO2 tank and a regulator may seem steep, you'll be able to refill these common CO2 tanks at a fraction of the cost. Most refills cost between $10-$30, and depending on how much CO2 you choose to inject, tanks of this size can last quite a few months for most hobbyists.

Refills can be handled at a variety of different locations, such as welding stores, beer distributors, and fire equipment stores. It's not uncommon for many of these stores to have pre-filled tanks ready to go, and instead of refilling your exact tank, you'll swap it with a pre-filled tank that they have in stock.

Canister CO2 setup
Miles/Light Fish
A 5lb CO2 canister housed underneath an aquarium

Our Favorite

Our favorite CO2 system is the Canister CO2 setup. While it may be the most expensive option up front, you'll save long-term on CO2 with easy tank exchanges and cheap refills.

However, as a planted tank owner, CO2 refills will be a task you'll need to do every so often. If there isn't a nearby location where you can get your CO2 refilled, you should probably go with whatever option is most convenient. For some folks that's disposable cartridges, and for others it might be a paintball CO2 tank. Whatever works best for your lifestyle!


That wraps up our list of the best types of CO2 systems for planted tanks. Do you have a favorite CO2 setup? Let us know in the comments, and be sure to visit our marketplace where you can buy and sell aquarium plants with other hobbyists.

Image of Miles Harrison

Miles Harrison

With over a decade of aquarium experience, Miles can be found writing about saltwater and freshwater aquariums. When he’s not writing about fish, you can find him going for a run or building websites, such as this one!