Product Reviews, CO2 System

Best CO2 Reactors for Reef and Planted Aquariums

Find out the best CO2 reactors for your planted tank with a 100% dissolution rate.

Easiest to Operate
The Best CO2 Reactor Option: FZONE 2.5L Aquarium CO2 Generator System
FZONE 2.5L Aquarium CO2 Generator System
Best Overall
The Best CO2 Reactor Option: CO2 Generator System Carbon Dioxide Reactor
CO2 Generator System Carbon Dioxide Reactor
Best Budget
The Best CO2 Reactor Option: Cesco Solutions Citric Acid
Cesco Solutions Citric Acid
The Best CO2 Reactor Option

All plants require CO2 to grow the right way, and aquatic tanks are not an exception. We all know that plants need carbon dioxide for photosynthesis to occur, which provides the plant with food and the right elements for its growth.

However, unlike most plants that get CO2 naturally, plants in an aquarium require external stimuli in order to get the necessary amount. This is done through the best CO2 reactors. Since your tank isn’t able to recreate the natural cycle of water and therefore can’t provide CO2, you need an agent that you enable in order for the dioxide to become a part of the ecosystem. 

The goal is to come as close as possible to this natural environment to avoid health problems to your plants, translating to problems for your fish.

Creating a CO2 system has never been easy but choosing a CO2 reactor will be if you follow our review. We will narrow down the best pics for planted, reef, and nano aquariums, as well as a comparison between a reactor and a CO2 diffuser.

  1. Best Overall: CO2 Generator System Carbon Dioxide Reactor
  2. Easiest to Operate: FZONE 2.5L Aquarium CO2 Generator System
  3. Best Budget: Cesco Solutions Citric Acid
  4. Best External: ista co2 reactor
  5. Best Value per Money: ZRDR CO2 Generator System Carbon Dioxide
The Best CO2 Reactor Option

How Does a CO2 Reactor Work?

This might be a little confusing, especially if you’re new to this whole thing. However, its basis insists on mixing the CO2 and the aquarium water and then sending it back to the tank. Reactors provide CO2 for closed systems since they can’t produce their own. Its only job is to increase the CO2 levels to the amount your tank needs. 

The way it works in detail is that in order to raise the CO2 level in the tank, you make the CO2 dissolve or exchange with the gases in the water by trapping the CO2 in the water column. To allow faster diffusion, all the turmoil caused aids in creating smaller bubbles with a higher surface area to volume ratio.

CO2 Reactor vs. Diffuser

To be fair, both products have the same principle, applied in different ways. While a CO2 reactor would use the water’s pressure to implement the CO2, the CO2 diffusers will make a more delicate job of it by creating tiny bubbles that “melt” into the water over time. 

A CO2 reactor might spare you the bubbles and seem more collected. However, it tends to be louder than a CO2 diffuser. The latter does a more satisfactory job indeed. It also requires a bit more dedication to the other parts of the ecosystem to keep everything balanced.

Out of the two, personally, I’d go with a CO2 diffuser for it’s the best choice for my tank. However, this is totally relevant to how you want the dioxide to be a part of your tank and at what rates. 

Also, suppose you’re into the aesthetic approach diffusers and especially in-tank diffusers. In that case, your tank will look more seamless, with the only visual setback being the bubbles (if you consider them as such).

The Best CO2 Reactor for Planted Tank Option

What to Consider When Buying the Best CO2 Reactor

A CO2 reactor, as simple may it be for what it offers, it’s that hard when you have to choose between different reactors. They all look similar and do the same thing, so how to distinguish between them? 

Things included in the kit like a CO2 regulator, pressure or solenoid gauge, bubble counter, CO2 diffuser, etc are always a plus if they come without additional purchases. All these functions contribute to a more complete ecosystem, and consequently, they make your life easier and keep your wallet heavy.

Besides these, you need to check up on the way each product does its job. One of the things that will save you a lot of work and money is paying attention to the chemicals that generate CO2 for that particular setup. 

These chemicals can either be things like baking soda or citric acid, which are more accessible and obviously economic. They can be specific ones like cartridges that you’ll need to purchase periodically. Another technical thing to notice is the pressure relief valve. These valves open when the pressure gets too much so that the CO2 system won’t explode. 

You need to ensure that the product you’re getting has the valve to avoid accidents with the gas buildup or even fluid leaks. 

Finally, the quality. I don’t feel like you need me to tell you that a good product needs to feel sturdy and strong in hand, nor those good products are characterized by the quality of materials they’re built with. 

Just keep an eye open for any indicators that the product you’re purchasing is strong enough to handle daily usage for a prolonged time in the future, and by keeping all we mentioned in mind, you’ll be good to go.

Best CO2 Reactors: Top Picks

Best Overall
The Best CO2 Reactor Option: CO2 Generator System Carbon Dioxide Reactor
Photo: Amazon.com

This kit will definitely be the last item ever on your shopping list for this type of product. It’s genuinely an incredible investment and comes with all you will ever need for your plant’s CO2 intake. From high-quality materials that assure longevity to efficiency and inclusiveness of basically all they could fit in this kit, this sounds almost too good to be true. 

This one checks all the boxes we mentioned earlier, from how it works, with citric acid and baking soda, to the pressure valve, the solenoid valve, and all that you could ever ask for. Sincerely an outstanding product that definitely deserves the best overall award.

Easiest to Operate
The Best CO2 Reactor Option: FZONE 2.5L Aquarium CO2 Generator System
Photo: Amazon.com

This product also comes in a kit that includes a valve, a regulator, a bubble counter, and a 2.5L stainless steel bottle. This one proves to be sturdy and well made from the instructions to set it up and then use it for months to come. The Fzone Co2 Generator is a high-quality solution for pumping CO2 into home aquariums. 

This generator produces high-purity carbon dioxide gas from a combination of citric acid, sodium bicarbonate, and water. The CO2 then passes through a patented regulator, which ensures a consistent gas output. A high-precision needle valve is also present in the kit, giving you the peace of mind that only a good quality kit can provide. 

The Fzone CO2 Generator comes with everything you’ll need to start a healthy CO2 environment in your tank by keeping your fish, plants, and tank safe.

Best Budget
The Best CO2 Reactor Option: Cesco Solutions Citric Acid
Photo: Amazon.com

If you’re a bit tight and just need a product to get the job done, this would be the way to go. Cesco Solutions 100 percent Pure Citric Acid is a citric acid powder that you may use to manually disperse CO2 into your planted tank. 

This is one of the best and most effective citric acid packages out there, and it’s incredibly easy to operate as well as highly effective regardless of the minimal effort it requires to work. 

Made for your convenience, this product also features a zip lock bag that means that you can open, use it and then seal it back. As for usage, you may use this citric acid to create your DIY CO2 reactor or use it as a reactant in a CO2 reactor. Either way, you’ll get fantastic performance, especially when you consider the product’s price point.

Best External
The Best CO2 Reactor Option: ista co2 reactor
Photo: Amazon.com

If you’re looking for an external reactor, go no further, ISTA will be the answer you’re looking for. One of the most effective proven techniques to distribute CO2 into planted tanks implemented on this reactor has been proven to minimize CO2 loss to 0. 

Unlike other models where some bubbles might escape to the surface and burst by resulting in a loss of CO2, this technology dissolute these bubbles fully without giving them the chance to burst and escape. 

This product is externally utilized and small in size as well as acid-resistant and impact-resistant. One of the main features of this model is that no electricity is required because it uses the flow of water from the filter. It’s simple to clean and maintain, and it comes with a reasonable price. One of the most notable products of the bunch, this one is sure to surprise you after each step.

Best Value per Money
The Best CO2 Reactor Option: ZRDR CO2 Generator System Carbon Dioxide
Photo: Amazon.com

If you want a full-featured CO2 system without breaking the bank, the ZRDR CO2 Generator System is a fantastic choice. This model, despite its modest price, radiates toughness and utility in every aspect. IT completely undermines models made of flimsy material with the tough stainless steel that builds the main components of this Reactor, making it robust and a delight for those with cotton hands who would have to spend some more money on repairs or replacements if the product was prone to damages

However, that’s not the only way it saves money. It comes with everything you need right out of the box, from the bubble counter and pressure valve to the installation tools and instruction guide. Furthermore, the gadget may be used without the need for specialized CO2 cartridges, so you can go all DIY with this one. The ZRDR seems to be made precisely for people who need an item that will cover all you need at an affordable price.

Our Verdict

These products mentioned above are definitely based on the years of experience of our team and the reputations of the manufacturers. Overall, constructing a good and functional planted tank isn’t that hard of a task with the right approach. 

You will need a system with high-quality materials that are simple to set up and safe for your plants and fish. Things that all models above provide. We hope that you found the right choice for you in the midst of the options we provided, and we are optimistic that whichever your choice, you can’t go wrong with it even if it’s not exactly what fits you. 

At the end of the day, we’re confident that you managed to find the best CO2 reactor for your aquarium, and we hope we helped you create the best CO2 system you could’ve.

How We Choose the Best CO2 Reactor

When going through the options on the market, our team spotted the best CO2 reactor out there and then reviewed them to come up with a list of products that we thought made a difference. 

Each product took weeks to be reviewed, and they all have their ups and downs that make them perfect for different case scenarios. However, regardless of your choice, we made sure that all the products are on par with the industry standard as well as they’re on par with the standard we put upon them so they’d be fitting to all people regardless of their situation. 

In the end, we managed to find several CO2 reactors with perfect price points and unmatched quality.

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I am Mario, a expert aquarist who is sharing his knowledge with everyone.

Keeping innocent fish and aquatic plants safe and healthy is my daily routine. With my experience and my passion for aquatic life, I will advise you through the long run of keeping an aquarium.

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