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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

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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

Jeffrey P. Verified Buyer 22nd Jun 2018

Outstanding quality, product as advertised, fast s...

Outstanding quality, product as advertised, fast shipping from UK to USA. Am exceptionally pleased with CO2 Supermarket. Outstanding quality, product as advertised, fast shipping from UK to USA. Am exceptionally pleased with CO2 Supermarket. SodaStream Cylinder Refilling Adapter
Tommy W. Verified Buyer 21st Jun 2018

Everything good except the regulator. Out pressure...

Everything good except the regulator. Out pressure gauge leaked alot, had to put in an o-ring. Tank pressure gauge however didnt work. Everything good except the regulator. Out pressure gauge leaked alot, had to put in an o-ring. Tank pressure gauge however didnt work. Pro Aquarium CO2 System with Adjustable Pressure for Planted Tank 20L - 500L


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Reply from CO2 Supermarket
We are sorry to hear this, Tommy, but this is the first we are hearing about the problem you've had. If you had told us then we would of course have assisted and arranged a replacement, but if you don't tell us there's a problem then how are we to know you're in need of assistance?

Trygve L. Verified Buyer 21st Jun 2018

Excelent in every aspects.

Excelent in every aspects. Excelent in every aspects. Essential Fertiliser & Minerals Mix - 500g
Zoubir E. Verified Buyer 20th Jun 2018

Completely matches the description fast delivery p...

Completely matches the description fast delivery packaging treat not yet tested Completely matches the description fast delivery packaging treat not yet tested Flat-Bottom Glass CO2 Diffuser - Extra Large for Aquariums up to 500L
Jason M. Verified Buyer 17th Jun 2018

Works great, simple and straight forward installat...

Works great, simple and straight forward installation Works great, simple and straight forward installation Regulator CO2 Bubble Counter With in-built Check Valve
Roger G. Verified Buyer 12th Jun 2018

Purchasing from this seller went with absolutely n...

Purchasing from this seller went with absolutely no problems at all. The product works perfectly for the job of filling Co2 paintball bottles from a Co2 fire extinguisher. So all is good with my purchase Purchasing from this seller went with absolutely no problems at all. The product works perfectly for the job of filling Co2 paintball bottles from a Co2 fire extinguisher. So all is good with my purchase Paintball CGA 320 Cylinder Refilling Adapter
Ole P. Verified Buyer 11th Jun 2018

Nice little device that works well with my Sodastr...

Nice little device that works well with my Sodastream cylinders. It was shipped the same day I ordered - well done! Nice little device that works well with my Sodastream cylinders. It was shipped the same day I ordered - well done! Advanced Adapter for SodaStream Cylinders
Scott R. Verified Buyer 10th Jun 2018

Great unit, a lot cheaper than at my local fish st...

Great unit, a lot cheaper than at my local fish store who wanted £80 for the same item Great unit, a lot cheaper than at my local fish store who wanted £80 for the same item CO2 Solenoid Valve with Integrated Needle Valve for Planted Aquariums
Roselyne S. Verified Buyer 10th Jun 2018

Perfect, fits very well to the sodastream bottle a...

Perfect, fits very well to the sodastream bottle and my solenoid valve. Perfect, fits very well to the sodastream bottle and my solenoid valve. Advanced Adapter for SodaStream Cylinders
Robin W. Verified Buyer 10th Jun 2018

Neat bi of kit and to overly space invasive. Advis...

Neat bi of kit and to overly space invasive. Advise you get an extention tube if linking to a distributor so it clears the cylinder handle and safety guard Neat bi of kit and to overly space invasive. Advise you get an extention tube if linking to a distributor so it clears the cylinder handle and safety guard CO2 Regulator with Solenoid & Dual Gauges for Horizontal Cylinder Valves
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