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5 Best Aquarium CO2 System for your Fish Tank

When you do the aquascaping for your aquarium, you want your fish to get the feel of an ocean bed. One of the best ways to do it is by keeping live plants in your fish tank. Having an aquarium means taking care not only of the fish but also of the plants in it. 

The plants in your fish tank need to be looked after, and a device that can help you do this with ease is the CO2 system for planted aquarium. While keeping a CO2 kit in your fish tank is not mandatory, it does improve the health and increases the life of your plants. 

Why CO2 is important

While the fish in your aquarium need oxygen to breathe, the live plants need CO2 to survive and perform photosynthesis using light and water. Plants’ oxygen is not enough for the fish, and you still need an air pump. The plants in an aquarium cannot survive on the CO2 given by the fish alone.

Plants thrive on decaying matter to create CO2 for themselves, but while cleaning the fish tank, this matter is removed, and the closed surroundings do not provide a sufficient amount of carbon dioxide to plants. 

If this matter is left lying in the fish plant, it will make your fisk ill, and removing it from the aquarium creates a deficiency of CO2 for the plants. In their natural setting, plants can access the substrate they get from mud and the decaying matter.

We reviewed some aquarium CO2 systems and have picked the five best kits that you must have in your fish tank.

An excellent CO2 kit must be easy to use and maintain, should give you value for money, should be of good quality, and must not look too unsightly in your fish tank.

We have kept these parameters along with their utility’s most critical factor while picking out these 5 CO2 kits.

Top pick: Silent CO2 system

  1. ST International CO2 Regulator

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This CO2 aquarium kit is easy to use, with its decompression gauge can be easily adjusted to infuse a steady flow of CO2.

Can use the CO2 regulator for this kit with disposable cartridges, and it comes with a professional-grade solenoid valve that is patented.

The adjustable decompression provides a steady and accurate CO2 inflow. You can control the number of bubbles you want to release in the water. 

If you own a medium or a large aquarium, this aquarium CO2 regulator would be ideal for it. This aquarium CO2 system has an all-inclusive voltage rating for global use (110v and 220v), and the regulator has a PSE and CR accreditation along with International Patent approval for ultimate safety. You can use both small and large CO2 barrels with this kit.

This CO2 system for the aquarium doesn’t heat the fish tank, and because of its minimal sound, it does not cause any stress to the fish.

It is value for money as its durability and good performance come at a reasonable price. However, this aquarium CO2’s maintenance might prove to be a headache if you cannot find its uncommon size washer for replacement.

● Energy efficient
● Minimal sound
● Effective
● Value for money
● Durable

● Difficult to find replacement parts
● No on/off indicator light

Top pick: High precision CO2 kit

  1. Double Sun Aquarium CO2 Regulator

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This CO2 kit has a 1.6-inch dual display gauge that allows you to read the cylinder pressure (0-3500 psi) and the output pressure (0-150 psi). The split-type solenoid dual valve has been designed keeping in mind the new-age technology. It makes this CO2 regulator safe and reliable.

It has a built-in bubble counter and a check valve function on the regulator, and they can be micro adjusted easily. This regulator’s power requirement is DC 12V, and there is a 1-year warranty on this aquarium regulator.

The regulator also includes one wrench, one hex wrench, and one extra seal ring. The aquarium regulator for this planted tank CO2 system data-preserver-spaces=”true”> comes with a long wire of 57 inches, so you do not need to worry about finding an electrical point close to the fish tank.

Once you set the flow rate with its solenoid valve, it does not have to be re-adjusted manually by turning the valve every day since the solenoid stops the flow. This solenoid valve can also be attached to a timer that will automatically start and stop the CO2 flow.

One of the most vital points that go in favour of this CO2 regulator is its strong compatibility. It is compatible with most brands of high-density tubing, and this does not affect its efficiency.

It works well with most CO2 diffusers, atomizers, and US standard CO2 tanks(CGA320 connector). You can use this CO2 regulator with all kinds of aquariums. Every connection on this regulator has a sealing ring that prevents air leakage.

You do not leave the CO2 kit running all night in an aquarium because the plants do not use it up unless they have light. If the equipment is allowed to run overnight,

the CO2 concentration will rise, and pH levels would drop, leading to dead fish. You should start the CO2 kit 30 minutes after the lights come on and stop the CO2 30 minutes before the lights go off. It needs to be done manually in this kit as there is no timer to do this. 

● The low power consumption rate 
● Low noise levels
● High precision readings 
● No air leakage

What we don’t like 
● Problems with the needle valve

Top pick: Auto-timer CO2 kit

  1. WuyouChy Carbon Dioxide Reactor Kit

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This CO2 system for aquarium is reliable, efficient, and a professional-grade CO2 generator. It produces high quality and pure CO2 as it operates on the acid-alkali reaction theory. One of the best features of this CO2 kit is that the solenoid valve can be synchronized with light using a timer.

The kit comes with all its accessories except the reactant, so you don’t have to buy them separately. Steel Bottle, Pressure Reducing Valve, Safety Valve, Fine Adjusting Valve, Check Valve, Solenoid Valve, Tertiary Filter, Bubble Device, Pressure Gauge, Diffuser, and Tube are included in the kit. A manual version of this aquarium CO2 kit is also available.

The CO2 output can be regulated using the fine adjusting valve, and the burst pressure is more than 200kg/cm2. The safety valve opens up if the pressure goes above the safe level.

This kit’s recommended reactants are 200g Sodium Bicarbonate or Baking Soda (NaHCO3) or 200g Citric Acid (C6H8O7). Installing the check valve is optional, and you can do it easily by cutting the tubes and placing the valve in between.

The CO2 kit comes with a better stainless steel bottle than the plastic bottles used by many aquarium CO2 kits. An excellent feature of this is its safety valve that opens automatically when the pressure crosses the safety mark.

The extra accessories and replacement parts for this kit like Solenoid Valve, Main Valve, Stand Base, Diffuser are readily available.

● Easy to install
● Auto-open safety valve
● Readily available accessories and replacement parts
● Safe, reliable, and efficient 

● Reactant not included with the kit

Top pick: Budget CO2 kit

  1. HYQO DIY CO2 Aquarium Plant System

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This CO2 generator helps create a natural environment for the plants in your fish tank by infusing carbon dioxide in water. The CO2 kit comes with a pressure gauge for displaying the pressure.

This CO2 DIY kit comes with an ABS engineering plastic cover and a locking pipe device to ensure the tubes’ non-deformation. The gas adjusting valve used to provide a steady flow of CO2 DIY is made of good quality metal.

You would need to arrange two plastic bottles of 2L each for using this with this CO2 kit. If you do not find DIY activities interesting, you might find it exhaustive to arrange for all the parts and setting up this DIY CO2 regulator kit.

However, this DIY CO2 is suitable for hobby aquarists and an excellent choice for someone who wants a CO2 kit on a budget.

● Easy to operate
● Easily adjustable gas levels 
● Non-slip wire 
● Good buy in the budget category of CO2 kits

● Diffuser and bubble counter not included with the kit
● Challenging to install for amateurs

Top pick: Reliable CO2 kit

  1. JIAWANSHUN CO2 System for Aquarium 

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This CO2 kit is a sleek system that generates carbon dioxide for your aquarium plants and keeps them in good health by allowing them to perform photosynthesis.

This kit comes with a stainless steel cylinder that is durable and sturdy. The CO2 generator kit includes the gas cylinder, solenoid valve, fine-tuning valve, pressure relief valve, three-stage filter, diffuser, bubbler, check valve. The operating instructions for this kit are also included along with these accessories.

The safety valve in this kit releases pressure when it reaches 70kg/cm, and the solenoid valve can be used with a timer to synchronize it with the light.

It helps the plants in performing photosynthesis. The amount of carbon dioxide needed to be infused into the water depends on the aquarium’s size. Its stainless steel diffuser allows the gas to be mixed well with the water.

You can adjust that using the fine-tuning valve. Its triple filtration system effectively absorbs impurities and moisture in the gas and releases pure CO2 in the water.

A useful feature of this kit is that you can control the bubble speed with the bubble controller. When you synchronize the light and the CO2 infusion in the water, it leads to the plants’ rapid growth as they perform photosynthesis, and the timer in this kit helps in doing that.

The kit does not take up much space as the sleek bottle body can also fit inside the aquarium, and you can select the length of tubing you wish to get with this kit from 20/25/30/35 and 40 cm in heights.

● Automatic pressure release 
● Safe and reliable
● Timer
● Sleek and compact 
● Adjustable tubing length

● Kit starter materials not included.
If you have live plants in your fish tank, these CO2 aquarium kits are going to assist in their rapid growth and health. 

Frequently Asked Questions

When do you need a CO2 aquarium kit?

The CO2 system for planted aquariums adds the required amount of CO2 to the fish tank and creates an environment for your live plants to thrive.

A planted aquarium needs light, soil and its nutrients, and an ample amount of CO2. These kits replicate the natural environment for the plants. If you wonder whether you need one of these for your aquarium, let’s tell you why and when you need one.

For live plants

CO2 aquarium kit is needed in a fish

tank with live plants since this kit’s primary purpose is to infuse CO2 in the water for these plants. The fish in your tank does not need this kit.

Light source

Fish tanks that get a high or medium amount of light need this kit for the plants’ health that proliferate in more light. Faster growth means an increased need for CO2.

For aquariums that get low light, the breakdown of plant matter, fish respiration, and surface agitation cause CO2 from the surface to get mixed in the water is generally enough.