Free UK Shipping
On Orders £30+. Next Day on Orders £80+
Same Day Dispatch
Weekday Orders Placed Before 3pm
Free Returns
100% Satisfaction Guaranteed
Lifetime Support
With Extended Warranties
Free UK Shipping
On Orders £30+. Next Day on Orders £80+
Same Day Dispatch
Weekday Orders Placed Before 3pm
Lifetime Support
With Extended Warranties

Aquarium CO2 Systems

Give Your Aquarium Plants the CO2 They Need to Grow and Flourish

View Our Range
of CO2 Systems

Click Here to View

Consistently Receive Good Feedback

Our Customers Rate Us

4.8 / 5

Based on 2,254 Customer Reviews.
Providing Excellent Customer Service for 6 Years.

How a CO2 System Will Give You Better Plant Growth in Your Aquarium

If you constantly need to re-stock your aquarium plants because they either die, become overgrown with algae or generally have poor health then you're not alone. It's a problem that *every* person owning an aquarium has faced at one time or another. But how is it that people are able to create scenes like this...

Aquarium CO2 System shown in a planted tank

...and yet your plants seem to die a few weeks after you planted them? They must be doing something different, right? Correct! Let's look at exactly what they're doing and how you can replicate those results in your own aquarium.

Your Aquarium is a Closed Ecosystem

The most important aspect you need to consider is that you are creating an artificial world for your plants and fish, encased within glass or plastic. What that means is the nutrients and elements that your plants need don't occur as they do in the wild, and just as you feed your fish to satisfy their needs, your plants also need to have their needs satisfied too.

No CO2 = No Photosynthesis = Dead Plants

Diagram of Photosythesis with and without CO2.

"Photosynthesis" - we all learnt about it in school didn't we? No doubt you know this already, but just to refresh, here's a definition of Photosynthesis:

"Photosynthesis is a chemical process through which plants produce glucose and oxygen from carbon dioxide and water, using only light as a source of energy."

Essentially, what this means is without a source of Carbon Dioxide, your aquarium plants can't properly Photosynthesise to produce the sugars they need to survive. Or to put it another way: No CO2 = A Dead Plant.

But how do you give your aquarium plants CO2? Thankfully, it's not as difficult as you might think; just as you use an air pump to pump Oxygen into your aquarium, you can buy Aquarium CO2 Systems to pump Carbon Dioxide into your tank. We'll look into that more further on.

Nutrients & Elements

Any plant, whether aquatic or terrestrial, needs a variety of nutrients to grow and maintain a good state of health. In the wild these nutrients are provided by natural means but because an aquarium is a closed ecosystem those nutrients must be supplemented to maintain strong growth and good health. If those nutrients aren't supplemented the plant will eventually die, or certainly have a lacklustre appearance.

Plants require nutrients at different rates and volume, some are required at higher volumes, such as Potassium (K), Phosphorus (P), and Nitrogen (N) - these are known as 'Macronutrients'. Other nutrients are also required, but at lower amounts or concentrations. These are know as 'Micronutrients' and include elements such as Boron (B), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn).

But how do you go about sourcing those nutrients and elements? They sound more like things you'd find in a Science laboratory rather than a pet store. Well, just as with the CO2 aspect, we can help with this too.

How CO2 Supermarket Can Help You

Since 2010 we have been supplying the world's aquascapers with everything they need to create their own beautiful planted aquarium. For your convenience, we supply pre-bundled CO2 Systems for diffusing CO2 in your aquarium water, and also complete aquarium fertiliser mixes that contain all of the required nutrients and elements to sustain vigorous plant growth in your aquarium.

Our Aquarium CO2 Systems Comprise Of

  1. Easy CO2 Adapter (optional)
  2. Gas Regulator
  3. Bubble Counter
  4. CO2 Diffuser
  5. CO2 Drop Checker
  6. High-grade CO2-resistant tubing
Let's explore the role of each of these parts

Easy CO2 Adapter

Photo of a SodaStream adapter sold in CO2 Systems from CO2 Supermarket. Photo of a SodaStream adapter in use.

One problem you may encounter while operating your CO2 system is actually sourcing the CO2 cylinders needed for your system. Our range of CO2 systems come with an (optional) adapter that enable you to use a range of easily accessible CO2 cylinders as your CO2 source. These include: SodaStream cylinders, Disposable Welding CO2 cylinders, or Paintball CO2 cylinders - simply select which type you'd like.

By using one of these adapters, you are ensuring that a supply of CO2 is always conveniently available from a high street shop. Our CO2 Systems are customisable to enable you to select which adapter you would like to use.

Gas Regulator

Photo of a gas regulator contained in a CO2 System from CO2 Supermarket.

A gas regulator is needed to 'regulate' the high pressure from the CO2 cylinder to a lower, usable pressure for use in the aquarium. Our range of regulators are purpose-built for aquarium use and very safe, easy to install, and use.

The regulators included in our Aquarium CO2 Systems come with an integrated solenoid magnetic valve, which enable use of a timer plug to turn the CO2 off when the lights in your aquarium are switched off and the plants are not Photosynthesising.

Bubble Counter

Photo of a bubble counter attached to a co2 regulator.

A bubble counter is a simple but effective piece of equipment that enables you to monitor the dosing of CO2 into your aquarium. By counting the number of bubbles flowing through the unit, you can adjust the flow controller on the regulator to achieve the 'bubble count' you require.

For example, for a 150L aquarium a bubble rate of 60 bubbles / minute is a good starting point.

The bubble counters that we sell also include an integrated 'check valve' (aka 'one-way valve') that will prevent water from siphoning down the tubing from the aquarium and into your regulator, possibly causing damage.

CO2 Diffuser

Photo of a CO2 diffuser.

Going back to our school days again, in Science lessons we learnt that the rate of a reaction can be increased by increasing the surface area of the reactant, e.g. turning a solid block into a powder. The same principle applies to diffusing the CO2 in your aquarium water; the more surface area the CO2 has in contact with the water, the better the level of diffusion you will achieve. The way to do that is produce very small bubbles of CO2, rather than one large bubble.

The part responsible for this is the 'CO2 Diffuser'. The diffuser emits very small bubbles of CO2. The smaller the bubble, the more surface area, and the better the level of diffusion achieved.

We stock a wide range of diffusers, but the type included in our CO2 systems are known as 'atomizer' diffusers. Atomizer diffusers, as the name suggests, produce incredibly small bubbles of CO2, and therefore achieve very high levels of diffusion.

CO2 Drop Checker

Photo of a CO2 drop checker kit.

A drop checker is deployed within the aquarium and changes colour to reflect the level of CO2 in the aquarium water; yellow indicates too much CO2, blue indicates low CO2 levels, green indicates correct CO2 levels. This eliminates any guesswork as it enables the correct level of CO2 dosing for a specific aquarium. Adjustments can be made using the flow controller on the regulator, and using the bubble counter to monitor the dosing level.

The solution for the drop checker comes pre-mixed, so set-up and installation is done in just a couple of minutes.

CO2-Resistant Tubing

Photo of co2-resistant polyurethane tubing.

To connect your pieces of equipment together you will need to use tubing. It is not recommended to use the same PVC or Silicon tubing used for an air pump because it will react with the CO2 and will eventually crack or become porous, resulting in a leak. Instead we supply high-grade CO2-resistant Polyurethane tubing, which will not react with CO2.

Our Commitment to Customer Service

Over the years we have helped thousands of people successfully install and operate their CO2 system without problem. All of our equipment comes with in-depth installation instructions, and we're always on-hand to provide assistance if needed.


Most Popular

Customer Reviews

Average Rating

Individual Reviews

Clive H. Verified Buyer 20th Jan 2018

Works very well and superbly well-made. I've refil...

Works very well and superbly well-made. I've refilled around 5 cylinders over the past few months and I can't fault it. Works very well and superbly well-made. I've refilled around 5 cylinders over the past few months and I can't fault it. SodaStream Cylinder Refilling Adapter
Phillip . Verified Buyer 19th Jan 2018

working well good little solenoid, very quiet

working well good little solenoid, very quiet working well good little solenoid, very quiet CO2 Solenoid Valve with Integrated Needle Valve for Planted Aquariums
Karen . Verified Buyer 19th Jan 2018

Worked at first though not well and after 3 months...

Worked at first though not well and after 3 months just leaked and would not refill my Sodastream cylinder. Worked at first though not well and after 3 months just leaked and would not refill my Sodastream cylinder. SodaStream Cylinder Refilling Adapter


Small logo for CO2 Supermarket
Reply from CO2 Supermarket
I'm sorry to hear this Karen. The seal within the adapter doesn't last forever and will need to be replaced periodically. They are available via the website. We'd always recommend having some spare on-hand ready for when they're needed.

Jan N. Verified Buyer 16th Jan 2018

very good mix, have used it before, all your plant...

very good mix, have used it before, all your plant needs, I just have to adjust it to my local water values. super quick delivery time, even to Denmark very good mix, have used it before, all your plant needs, I just have to adjust it to my local water values. super quick delivery time, even to Denmark Essential Fertiliser & Minerals Mix - 250g
Darran L. Verified Buyer 15th Jan 2018

Nice easy instructions to get the whole system set...

Nice easy instructions to get the whole system set up in a fairly short period of time. The drop checker has been really handy, have seen that go from blue to green and can be confident I am not overdosing as it has not gone to yellow.I have followed the instructions to place the bazooka below the output of the filter and can see the tiny bubbles spending a long time moving within the water rather read more... Nice easy instructions to get the whole system set up in a fairly short period of time. The drop checker has been really handy, have seen that go from blue to green and can be confident I am not overdosing as it has not gone to yellow.I have followed the instructions to place the bazooka below the output of the filter and can see the tiny bubbles spending a long time moving within the water rather than just rising to the surface and escaping. But most importantly after one week I can see new plant growth on at least seven different types of plants, also I am even starting to see a visible reduction on the algae on ornaments now the algae eaters seem to be able to start to get ahead. Complete Aquarium CO2 System for Planted Tank 80L - 500L
David C. Verified Buyer 14th Jan 2018

Excellent product, saves lots of setting up every ...

Excellent product, saves lots of setting up every morning Excellent product, saves lots of setting up every morning CO2 Solenoid Valve for Planted Aquariums
Nico V. Verified Buyer 14th Jan 2018

Am super satisfied with my Refill Adapter. Today f...

Am super satisfied with my Refill Adapter. Today first test done without problems. Have now a co2 filling of 1.50 euro i.p.v 10 euro. Am super satisfied with my Refill Adapter. Today first test done without problems. Have now a co2 filling of 1.50 euro i.p.v 10 euro. SodaStream Cylinder Refilling Adapter
John E. Verified Buyer 13th Jan 2018

This item was suggested to me as it would solve th...

This item was suggested to me as it would solve the problem of fitting a solenoid switch to my co2 system. And it does that. I’m happy. This item was suggested to me as it would solve the problem of fitting a solenoid switch to my co2 system. And it does that. I’m happy. 57mm Extension
Jon W. Verified Buyer 13th Jan 2018

This does work although I had a rogue cylinder tha...

This does work although I had a rogue cylinder that needed a bit ground off the neck as it did not seat properly but my second cylinder fitted well. My cylinders were the original steel ones as supplied in the UK. This does work although I had a rogue cylinder that needed a bit ground off the neck as it did not seat properly but my second cylinder fitted well. My cylinders were the original steel ones as supplied in the UK. Advanced Adapter for Australia and New Zealand SodaStream Cylinders
Paul B. Verified Buyer 11th Jan 2018

Easy to assemble kit, containing all I need for a ...

Easy to assemble kit, containing all I need for a 60l tank. Needle regulator allows for precise control of CO2 delivery, enabling me to vary the drop rate to within +/-0.5s. The system has only been running for a few days, so the impact of CO2 in the tank, and particularly the elimination of algae, is yet to be determined. Easy to assemble kit, containing all I need for a 60l tank. Needle regulator allows for precise control of CO2 delivery, enabling me to vary the drop rate to within +/-0.5s. The system has only been running for a few days, so the impact of CO2 in the tank, and particularly the elimination of algae, is yet to be determined. Nano Aquarium CO2 System for Planted Tank 20L - 100L
See more reviews  Loading
Cart Activity

Someone added a product to their cart

View Product

Someone added a product to their cart

View Product