CO2 Supplies

Find Aquarium CO2 Regulators, Diffusers and Complete Kits 

Aquarium CO2 supplies help live plants grow healthier and more vibrant by providing the carbon dioxide they need to thrive. Our collection includes everything from complete CO2 systems to individual components like regulators and diffusers, tailored for a range of planted tank setups.

Whether you’re starting fresh with your first planted aquarium or upgrading your current gear, these products support better plant growth, reduced algae, and clearer water.

If you keep live plants and want to boost their colour and growth, CO2 equipment is a game-changer. Full aquarium CO2 systems are great for beginners because they come with everything you need to get started. More experienced aquarists may prefer picking out separate components to customize their setup.

Some popular options include diffusers like the Twinstar CO2 Diffuser and Tropica CO2 Diffuser to efficiently dissolve CO2 into water, pressure regulators like the Strideways PRO CO2 Regulator, and safety tools like the AquaEL Check Valve. The right choice depends on your tank size, from compact inline diffusers to powerful reactors for densely planted aquascapes.

When choosing your CO2 gear, start by matching equipment to your tank size and the density of your plants. Beginners should consider complete aquarium CO2 kits that include the regulator, diffuser, and monitoring tools, all designed to work together.

Always make sure your CO2 cylinder and accessories are compatible: thread sizes and pressure ratings matter. Also, investing in a quality regulator and solenoid valve helps reduce CO2 waste and keeps levels steady for optimal plant health.

Start with low CO2 levels and raise them gradually to avoid stressing your fish or triggering sudden pH swings. Position the diffuser near areas of good water flow (but not too close to filter outlets, which can disperse CO2 too quickly). Use a drop checker to monitor CO2 levels and aim for a light green colour, which indicates the balance is just right. Avoid running CO2 at night, since plants don’t absorb it after lights out. Not only is it wasted, but it can also lower pH and affect your fish.

CO2 supplies can make a big difference in the health of your plants, the clarity of your water, and even your fish’s well-being. A good CO2 system brings out the full potential of a planted tank, creating a lush, balanced ecosystem that’s easier to maintain in the long run. Check out our extensive collection of aquarium CO2 supplies to find the right product that works for you.

FAQs About CO2 Regulators and Diffusers

(1) What do I need for a CO2 aquarium?

To get started, you’ll need a CO2 tank (or generator), a regulator, a diffuser, and tubing. Beginner kits like the ARKA myScape Bio CO2 Starter-Set come with everything you need. For more advanced setups, extras like check valves and solenoid valves offer added safety and control.

(2) What is the best CO2 diffuser?

It depends on your tank size. The Twinstar CO2 Diffuser is ideal for smaller tanks, while larger aquariums do better with the Tropica CO2 Diffuser. Choose based on your tank volume and whether you prefer ceramic or glass materials, as both dissolve CO2 efficiently.

(3) What size CO2 tank should I get?

Your CO2 tank size depends on how big your tank is and how many plants you keep. Nano setups under 50L do fine with smaller systems, while 2L tanks like the Strideways CO2 Aluminum Bottle are better for larger aquariums. Bigger tanks mean fewer frequent refills.

(4) How do you know if your aquarium needs CO2?

If your live plants are growing slowly, turning yellow, or if algae is taking over, your tank could benefit from added CO2. Most planted tanks, especially those with high lighting, respond well to CO2 supplementation.

(5) Is DIY CO2 worth it?

DIY CO2 setups can work for basic tanks, but they need constant attention and frequent recharging. Bio systems like the Tropica CO2 System BIO offer better consistency with less maintenance. For serious plant growth, pressurized systems give you more control and reliability.

(6) How long can CO2 last in a tank?

It varies based on tank size, plant load, and CO2 method. Bio systems like Tropica’s typically last 1–2 months, while a pressurized 2L system may run for 3–6 months in smaller tanks. Heavily planted tanks use CO2 faster and will need more frequent refills.

(7) Should I turn off CO2 at night in an aquarium?

Yes! Plants only use CO2 during the day. Running it at night wastes gas and can drop pH levels, putting your fish at risk. Use a timer or solenoid valve (like the one in our Strideways PRO Regulator) to automatically shut it off when the lights go out.