Name: Aquario Neo CO2 Kit Refill
Brand: Aquario
SKU: AQUNCO2R
Price: 11.99 USD
Availability: InStock

Aquario Neo CO2 Kit Refill

$11.99 USD

Usually ships in 1-2 business days from our fulfillment center

The NEO CO2 Kit REFILL is intended for use with the Aquario NEO CO2 Kit. You will receive one bag of Bio Powder ONLY. Please see the full kit HERE.

Hassle-free and budget-friendly CO2 injection solution
Comes with everything you’ll need
Ideal for beginners and hobbyists alike

The video below demonstrates how to properly setup Aquario Neo CO2:

Additional Information:

The Neo CO2 Kit is designed for aquariums between 10 to 30 gallons. Using this kit for nano aquarium tanks runs the risk of providing excessive CO2 resulting in the depletion of oxygen. This can be potentially deadly for livestock. However, this kit can be used in smaller aquarium tanks if oxygen is provided via air pump, air stone or surface agitation.

The life of the Neo CO2 Kit varies depending on the temperature. The recommended usage temperature ranges from 68° to 86°. As a general rule of thumb, this kit will last between 30 to 50 days during winter and 40 to 60 days during summer.

Gas output is not adjustable. The use of needle valves, solenoids, or other CO2 adjusting devices is not recommended as this can cause damage to the Nature Bottle.

Do not tilt or shake the bottle during operation in order to prevent reaction liquid from siphoning into the aquarium. It is normal for minor amounts of alcohol to be produced from the kit solution: this is harmless. In the event that any reaction liquid leaks into the aquarium, an oxygen deficiency can occur. A simple 30-50% water change will correct the issue as well as introducing an air pump to degas the CO2.

Clean and remove any gel that forms on the bottleneck before initial use to prevent build-up or blockage of the gas outlet. If any reaction liquid is found inside the flexible tubing, simply clean with lukewarm water.

The video below demonstrates how to properly reset Aquario Neo CO2:

Why CO2 injection is important in a planted tank: 3 main factors contribute to the optimal growth of aquatic plants. These factors include nutrients, light and carbon dioxide (CO2). If any of these are unbalanced, the results are algae growth or the withering of plants. The introduction of CO2 in a planted aquarium allows plants to thrive and grow more efficiently, while also giving them the ability to out-compete algae for nutrients.

No matter what type of planted aquarium setup you have, we recommend CO2 injection for better aquarium plant growth.

Usage Instructions:

Step 1: Water
Add 300ml of warm water. Do not add water that is too hot as it may damage the bottle and impact performance.

Step 2: Shake
Tighten the cap and shake well to ensure the solution is thoroughly mixed.

Step 3: Wait
Allow the Neo CO2 bottle to sit for 24 hours without interruption or disturbance. The liquid will thicken to a gel-like consistency. After 24 hours, invert the bottle to ensure that the liquid is fully solidified. If not, wait another hour and check again.

Step 4: Activate
Remove cap and clean off any gel that remains on the bottleneck. Add 1 packet of Neo CO2 Bio followed by 1 cup (200ml) of lukewarm, room temperature water around 77°. Reinstall the cap onto the bottle, no shaking is required. Connect flexible tubing on one end of the reaction cap and the other through the suction cup and onto the diffuser. Place the diffuser into your aquarium and wait.

Step 5: React
During initial use, CO2 gas output will fluctuate; however, the reaction speed will stabilize and slow down over time. The Neo CO2 Bottle will continue to work for up to 60 days depending on room temperature.

Step 6: Repeat
When CO2 output slows down or stops completely, remove the cap and pour the liquid out. Repeat steps 4 through 5 until the gel is fully consumed.

Includes: NEO CO2 Bio Powder Refill Bag

Aquario offers comprehensive support for planted aquariums, with products that combine design, performance, and ease of use. Their innovative CO2 diffusers and the Neo Flow series were a game changer for modular filtration gear that utilizes PETG—a flexible, clear, shatterproof alternative to traditional glass. With a further expansive line of water conditioners, fertilizers, and aquarium soils, Aquario equips hobbyists with premium planted tank supplies that support efficient, naturally beautiful aquascapes, making it a trusted go-to source for aquascapers who value both aesthetics and technical reliability.

Shop all Aquario

Ultimate Planted Aquarium CO2 Guide

Adding CO2 to a planted tank might seem complicated at first—with all the gear and technical terms, it’s easy to feel overwhelmed. However, once you understand the basics, setting up a CO2 system for your planted tank is just as straightforward as setting up a filter or light. We’ll walk you through everything you need to know step-by-step.

Aquario Neo CO2 Diffuser Normal Large injecting micro CO2 bubbles

What is CO2 and why is it important in a planted aquarium?

Just as we need oxygen to survive, aquarium plants rely on carbon dioxide to thrive. CO2 is naturally produced by fish, humans, and other animals, providing plants with what they need. In a freshwater tank, fish naturally produce small amounts of CO2, which can give the impression that some aquatic plants don’t need it. In reality, all plants require it, just at different levels. This is why CO2 injection systems are strongly recommended—Popular beginner plants like Anubias, Bucephalandra, Java Fern and aquatic mosses are commonly labeled as “low-tech” because they can handle minimal levels. However, even hardy plants benefit greatly from added CO2 and will grow more quickly and vibrantly with it.

Aquascaper’s Notes: During photosynthesis (lights on), plants release oxygen, which helps keep the water well-oxygenated for livestock. As a result, most aquascapers skip traditional airstones or bubblers.

Easy beginner low light aquarium plant Java Fern Trident

Microsorum pteropus AKA Java Fern 'Trident' producing oxygen

Okay, so aquarium plants need CO2, but what does it really do?

For proper growth, aquatic plants require a balanced mix of light, nutrients and CO2. Think of it like a pie—each slice represents one of these elements. If any slice is too small, large or missing, the pie is incomplete and represents an imbalance aka ideal conditions for algae to take over. Injecting CO2 into a freshwater planted tank improves plant health, and stability. That’s why we recommend CO2 systems even in low-light or beginner-friendly tanks. It completes the pie, creates balance and reduces the risk of algae problems.

Common examples of planted aquarium imbalances:

Too much light, but not enough CO2 or nutrients
Too much nutrients, but not enough CO2

What equipment do I need to start injecting CO2?

The process is simple, once you understand must-have gear. Here are our four essentials every planted tank hobbyist should have.

1. CO2 Regulator

Controls overall output levels. Each regulator will have at least one gauge that will display the maximum output pressure. We typically set this anywhere between 25-40PSI (safe range) on the main valve and fine-tune the flow with the needle valve (the smaller one) to dial in levels being injected. Dual-gauge regulators show both working pressure and available gas reserves in the cylinder. Higher-end models may also include a solenoid. A solenoid lets you shut off CO2 manually or with a timer—usually synced with the lights, since aquarium plants will not require it when lights are off.

Shop UNS Mini CO2 Dual Stage Regulator CO2 - Glass Aqua

Almost all CO2 regulators will have a gauge that displays maximum output pressure

Shop UNS Pro CO2 Dual Stage Regulator CO2 - Glass Aqua

While other CO2 regulators will have dual gauges

Main pressure valve on an Ultum Nature Systems Mini CO2 Regulator

Needle Valve on an Ultum Nature Systems Mini CO2 Regulator

Ultum Nature Systems UNS Dual Gauge CO2 PRO Regulator for Planted Aquariums

CO2 Regulator solenoid example

2. Cylinders & Cartridges

These store CO2. How long do they last? This is one of the most common questions we get—and the honest answer is: it depends. Every aquarium is different. Factors like tank size, aquarium water chemistry, plant variety, plant density, and CO2 injection levels needed all impact how quickly a cylinder or cartridge is used up. Here are some guidelines:

Cartridges: Single use, compact and convenient. They are the perfect desktop solution for nano tanks between 1 - 8 gallons.
Paintball Cylinders: Budget-friendly option that is popular for convenience, size and ease of use. Most can be refilled at related hobby (paintball) stores. A great option for aquariums up to 20 gallons.
Standard CGA-320 Cylinders: Don’t let the name intimidate you! A CGA-320 is a North American standard that can be refilled at most welding, air-supply or local brewery shops. This is our top recommendation for all aquascapers who are invested in the planted tank hobby. This type of cylinder holds the most and will require less refills in between uses.

Planted Aquarium CO2 Injection Equipment

3. CO2 Diffuser

Delivers CO2 in the form of ultra-fine bubbles into the aquarium. Some aquarium airstones may look similar to CO2 Diffusers, but these aim to produce larger bubbles for surface agitation and gas exchange. The larger the bubbles, the more the aquarium will be oxygenated. CO2 needs to be easily dissolved in a planted aquarium, which means the smaller the bubbles, the better.

4. CO2-Proof Tubing

This is important. Normal airline tubing for aquariums cannot handle the higher pressure of CO2 systems. Specialized CO2 proof tubing is built to withstand pressurized CO2 and allows it to travel safely into an aquarium without leaks.

Ultum Nature Systems Pro CO2 Tubing | Planted Tank CO2 - Glass Aqua

Optional CO2 Equipment

1. Bubble Counter: Not required, but a helpful tool! Bubble counters provide a visual reference in the form of bubbles for how much CO2 is being injected into the tank.

2. Drop Checker: This small glass accessory hangs on the rim of the tank or suctioned to a glass panel inside the aquarium. They typically include a liquid solution that changes colors based on the amount of CO2 injected.

Yellow means too much CO2, blue indicates too little, and green means the levels are just right. It can take a few hours following installation or a water change to change colors!

Ultum Nature Systems Micro CO2 Bubble Counter | CO2 - Glass Aqua

Ultum Nature Systems UNS CO2 Drop Checker

If you’ve read this far, we hope you now have a better grasp on planted aquarium CO2 injection. If you’re still not sure and a full setup feels like too much, we recommend starting out with a simple CO2 Kit. It’s easy to use, beginner-friendly and great for many tanks! But if you’re ready to make that leap and full send into CO2 injection, check out our bundled CO2 Kits at discounted prices. As always, if you have any questions, our team is always happy to help!

Shop Planted Tank CO2 Kits

Overall rating: 4.8536587 / 5 from 41 reviews.

AI Generated Review Summary

The Aquario Neo CO2 Kit Refill is praised for its budget-friendly and cost-effective CO2 injection solution, ideal for beginners and hobbyists. It provides essential CO2 for optimal plant growth in aquariums, though caution is advised for smaller tanks. The kit includes everything needed for setup and maintenance, ensuring hassle-free CO2 injection.

Summary topics

CO2 Kit Quality: 21%
CO2 System Cost-Effectiveness: 21%

Review topics: ["customer service","kit","system","co2","tank","directions","plants","option"].

Review highlights

"Such a great simple system, budget friendly and works great!" — Taran H.
"Good inexpensive co2 kit" — Trinity W.
"Arrived very quickly, unlike the site where I had ordered the starter kit, where it took a LONG time gettin the goods." — Yuen M.

Reviews

"This product worked great for my 7. 8-gallon tank. Less than 24 hours after adding the CO2 kit, I could already see my newly planted plants pearling. It’s a very easy-to-use kit and a great option for anyone just getting into the hobby."

— Abigail (5/5)

Great Customer Service

"To no one's fault, except the unexpected freezing weather. . Some plants 🪴 were DOA. . The customer service was very good polite and settled the issue quickly and to my full satisfaction!!. ."

— Hobert I. (5/5)

Good

"Works to get system started"

— Adolfo S. (5/5)

Bubbles on a Budget!

"Quality product for the dough. Works well and acts as described. Entry level CO2 kit that yields good plant growth when paired with a good light. Still getting it dialed in, but so far, so good. . ."

— Jonathan U. (5/5)

Worth for money

"Working good with my 5 gallon tank."

— sarith n. (5/5)

"Works great 👍🏽"

— Catherine (5/5)

mid

"It’s alright but I think I’d need two or three more in my tank to make any difference. Looking into a pressurized system now. It can’t turn my dropper from blue to green."

— Morgan O. (3/5)

So far so good

"This system is incredibly easy to setup and puts out a decent amount of CO2, will more than likely buy another one for my big tank!"

— Brandon H. (5/5)

Good, but you need to manually control if you go overboard on C02

"Hard to control, but good in a pinch when you're trying to see if C02 makes a difference. Definitely use with a drop checker."

— TINA N. (4/5)

Q&A

Shipping
Orders are typically processed within 1-2 business days M-F. However, additional time may be required during peak seasons and federal holidays. For orders containing live plants, we exercise extra caution and assess factors such as travel distance and weather to ensure safe transit.

To avoid delays, please ensure all order information is accurate and complete. We cannot offer refunds and are not responsible for orders shipped to incorrect addresses due to errors in provided information. Once an order has been shipped, delivery times are determined by the carrier and are outside of our control. On average, shipments arrive within 2–5 business days, excluding weekends and holidays. For more information, please visit our FAQ page.

Returns
If you are not satisfied with your purchase, please contact us within 48 hours of delivery. Approved returns must be shipped back within 14 days of approval. Returned items must be unused, unopened, and in their original packaging. Specific return requirements, if applicable, will be listed on the product’s page. For more information, please visit our FAQ page.

Refunds
No worries, we’ll take care of everything as long as it fits the guidelines above.Most answers to general questions can be found on our FAQ page.