FZONE 2.5L Upgraded Aquarium CO₂ System with Complete Accessories, CO₂ Generator kit with Integrated Solenoid & Bubble Counter, Safety Valve, Main Switch for Planted Tanks
Condition: New
Buy Now, Pay Later
As low as
$14.98
/ mo
Learn more
- – 6-month term
- – No impact on credit to apply
- – Instant approval decision
- – Secure and straightforward checkout
Ready to go? Add this product to your cart and select a plan during checkout.
Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Zip, Apple Pay, and Google Pay. No-credit-needed leasing options through Acima may also be available at checkout.
Learn more about financing & leasing here.
Selected Option
Free shipping on this product
30-day returns
Learn more
FREE 30-day refund/replacement
To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
Availability:
In Stock.
Arrives
Monday, Aug 3
Size: 2.5L
Features
- High-Efficiency CO2 Supply System: FZONE CO2 generator system uses a citric acid and sodium bicarbonate reaction to produce high-purity CO2, delivering stable pressure and flow through a CO2 regulator, bubble counter, and CO2 diffuser. Unlike traditional cylinder systems,it requires no refilling at CO2 stations, making it more convenient
- Enhanced Safety Design: The FZONE aquarium CO2 system is made from food-grade 304 stainless steel with body 50% thicker for greater strength and pressure resistance. The CO2 system includes a manual shut-off valve for safe control when CO2 is not needed, and an automatic pressure-relief valve that releases excess pressure when it rises above the safe limit,providing dual safety protection for worry-free operation.
- Precise and Reliable CO2 Control:The FZONE CO2 generator for plantsuses a precision needle valve for smooth, accurate flow adjustment. The bubble counter provides a clear view of CO2 injection rate, while the pressure gauge displays real-time tank pressure. Its upgraded all-in-one solenoid minimizes connections and leak risks, ensuring stable, consistent CO2 delivery for your planted aquarium.
- Ready to Use: This complete Aquarium CO2 kit is designed for easy setup and convenience. It includes all essential accessories CO2 diffuser, check valve, U-connector, suction cups, tubing, funnel, syringe, sealing rings, and power adapter no extra parts required. Just add the raw materials (not included) and youre ready to go.
- Easier Use and Maintenance :The DIY co2 reactor kit features an upgraded external thread design that prevents residue buildup, making cleaning simple and smooth. The bottle opens effortlessly without sticking, and the built-in fill port lets you add water directly with a syringe no need to unscrew the cap, saving time and effort.
Description
— Enjoy the Art of Aquascaping Founded in 2018, Fzone creates aquarium products that combine high quality with clean, aesthetic design. What began as a passion grew into a mission — to offer products that are reliable, precise, and visually refined. We focus on CO₂ systems and aquarium accessories that improve plant growth while keeping setups neat and elegant. Thank you for your support — we look forward to growing with you. FZONE CO₂ generator system, uses a citric acid and baking soda reaction to produce high-purity CO₂, delivering stable pressure and smooth flow through the regulator, bubble counter, and diffuser, delivering a stable and continuous CO₂ supply to support healthy plant growth in your aquarium. The FZONE Upgraded CO₂ Generator System is your perfect choice. It’s safe, easy to use, and ready right out of the box — providing a steady CO₂ supply for lush, vibrant plant growth. Solves the common problem of the regulator becoming hard to unscrew when replacing reactants Reduces connection points, minimizing CO₂ leakage risk and ensuring a more stable, reliable system Features a manual shut-off and pressure relief valve for dual safety protection
Package Dimensions : 14.57 x 11.73 x 4.92 inches; 4.48 Pounds
Item model number : FZ-GNRT
Date First Available : September 17, 2025
Manufacturer : FZONE
Best Sellers Rank: #27,415 in Pet Supplies (See Top 100 in Pet Supplies) #128 in Aquarium Air Pump Accessories
#128 in Aquarium Air Pump Accessories:
Customer Reviews: 4.4 4.4 out of 5 stars (89)
Item Weight: 4.47 pounds
Manufacturer: FZONE
Item model number: FZ-GNRT
Date First Available: September 17, 2025
Item Package Dimensions L x W x H: 14.57 x 11.73 x 4.92 inches
Brand Name: FZONE
Warranty Description: 1
Model Name: CO2 Generator
Color: Silver
Size: 2.5L
Number of Items: 1
Included Components: CO₂ Generator kit
Specific Uses for Product: Planted aquarium
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Monday, Aug 3
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
- Klarna Financing
- Affirm Pay in 4
- Affirm Financing
- Afterpay Financing
- Zip Pay in 4
- Financing through Apple Pay
- Financing through Google Pay
Learn more about financing & leasing here.
Similar Products
Top Amazon Reviews
Size: 2.5L
Bought this to provide CO2 to my new 10gal shallow planted tank. Ingredients were easy enough to source, directions are included on a sticker that can be attached to the tank, assembly is very straightforward. Components all seem to be good quality, and it fits well behind my tank. I will say that it had to sit overnight to build pressure, and didn't pressurize within the 1-2hrs that the directions said. For $72 (before tax) this is a much cheaper and more sustainable option than refilling CO2 tanks at the store. I tried the diffuser it came with but it's not the greatest, worked ok for a few days but it's basic plastic. I swapped it out for a UNS inline diffuser and I'm much happier with that. The included diffuser was tricky to drain- I ended up using the included syringe to force the water out, since it has no way to disassemble it. Not sure how long the ceramic pad is supposed to last on it, but note that it can't be swapped out and the whole diffuser would need to be replaced. Would absolutely recommend overall, great little system that is beginner-friendly.
...
show more
Reviewed in the United States on July 10, 2026 by Ryan
Size: 2.5L
I’ve run my DIY yeast and baking soda CO2 when I just started this hobby. Recently, I became more high-tech and started using injected CO2 systems. The FZONE 2.5L CO2 Generator System has honestly impressed me more than I expected. If you’ve been in the hobby long enough, you know that a CO2 setup is only as good as its stability, build quality, and fine control. This unit delivers on all three. Build & Design: The stainless steel body feels solid and professional, not flimsy like some DIY kits. All the seals, connections, and threads are tight and precise. It’s the kind of system where the moment you pick it up, you know it's engineered properly. The pressure gauge is clear and responsive, and the bubble counter has no lag or micro-leaks. Performance: What surprised me most is how consistent the output is. Many smaller generators fluctuate, but this 2.5L model holds pressure beautifully throughout the diffusion cycle. I get a steady bubble rate all day, which is crucial when you’re maintaining demanding plants like Rotala species and carpeting plants. Ease of Use: Setup was refreshingly straightforward. The instructions are clear, and everything you need is in the box. If you’ve ever assembled a DIY citric acid/baking soda rig, this feels like an upgraded, frustration-free version: safer, cleaner, and much more predictable. CO2 refills take just a few minutes, and I can run my 16-gallon tank for weeks before topping up. Efficiency: I pair this with a good inline diffuser, and the gas dissolution is fantastic. My pH drop is consistent, growth is explosive, and algae has backed off significantly. Don't believe me? Look at the pictures and judge for yourself. That's my tank with the CO2 paired with the Fzone Brite light. Honestly, if your plants aren’t thriving with this system, it’s not the CO2. Value: For the performance you get, the price is almost too good. You’re basically getting near-pressurized-cylinder stability without the hassle of renting tanks or lugging them around for refills. Final Verdict: If you’re a planted-tank hobbyist who cares about healthy, vibrant growth - and you want a reliable CO2 system without breaking the bank - this is one of the best setups you can buy. After years of using everything from regulator kits to full pressurized cylinders, the FZONE 2.5L generator has earned a permanent spot in my aquarium rotation. Highly recommended for beginners AND seasoned aquascapers.
...
show more
Reviewed in the United States on November 19, 2025 by joe
Size: 2.5L
I've had a lot of fun setting this CO² generator. This will be my third time using CO² and I'll say this now, this has been, and I anticipate it to remain, my favored method. Here are my experiences: It's clear the manufacturer has invested in ensuring everything arrives safely. Some of the components are glass, so having each part in a padded section made inventorying parts easy. The instrustions were clear and I was able to follow them during setup. The only trouble I had setting everything up was that I could not find my kitchen scale and had to get another. That's on me. Buying reagents online, I've noticed, dramatically increase the value. All the parts fit together well, and I will admit this setup is so much better than yeast generators and even other citric acid-based I've used in the past that required tubes from one to another to feed the reaction. This method, single tank, greatly simplifies the whole project. I went on a research rabbit-hole learning how this reaction works, and more interesting, how forcing CO² into the water in the generator has some buffering effect on the chemical reaction, but if the pressure gets too high there is a safety release built in. The bubble counter is pretty standard. I filled mine with 1/2 water and 1/2 glycerin. This keeps the bubble counter from evaporating too quickly. This also affects viscosity and you'll need to count the bubbles per second a little differently. Using the needle valve works effectively, but I did find I needed to do some very small adjustments back and forth to get my flow rate where I wanted. The ceramic diffuser has been working wonderfully. The bubbles are small, and by placing the diffuser under my filter outflow I can keep them in the water column longer for better gas exchange. I made sure to put my check valve close to the glass curve to keep as much water out of my system as possible. I will be picking up a new drop-checker soon but my old one is showing my CO² infusion is working. (Come on little dwarf baby tears, you can do it!) Construction is great. The tank feels solid and safe. Stickers for the tank are included, and the circular one required me to snip on edge to allow it to stay flat. Summary: Construction - great, feels safe to use under high pressure. Ease-of-Use - great, major improvement over other methods. Design - excellent - looks a lot better next to my aquarium thank other methods. Value - function/price result is a high value, especially for being efficient (pure CO² is chemical output) Inclusions - everything you need except the reagents are included, from diffuser to clips to tubing. I would recommend this system to local friends in the hobby.
...
show more
Reviewed in the United States on December 8, 2025 by Jayker
Size: 2.5L
Fzone CO2 generators are my go to for CO2 injection. I have a 75g, 29g, & 16g tanks all running Fzone generators. My 29g has the original 4l version that I purchased a while ago and has been running flawlessly. When they approached me about trying their new upgraded 2.5l kit I was excited to see if they addressed they few complaints I had with the original version. The new upgraded version has definitely improved for my set up. Most noteably, the instructions on the upgraded kit are vastly improved. The original instructions were very confusing and I had to source additional information online about the setup. On the new version, they are much clearer on how to set it up, what chemicals are needed, and how much to use. For someone who is purchasing their first setup, you should have no problems if you read them thoroughly. The second major improvement, which may not affect everyone, is the reduction in overall height. I am now able to fit both the larger 5l and the 2.5l in my cabinet. My original 4l was too tall to fit. The included parts are all very high quality and the diffuser included in the upgraded kit has a much larger surface air and produces much finer bubbles. The included CO2 tubing is much more flexible and easier to work with than the original. The new bubble counter has a fill port on the side of it as well as a small syringe so you don't have to remove it from the solenoid assembly when the water evaporates. I found this to be very fiddley and I had to have the angle of the syringe perfect or it would leak. I didn't find this method any easier than unscrewing the bubble counter to fill it and I probably won't use it again. The value of these generators can't be beat and he quality of the parts are excellent. No need to waste time driving to get tanks filled. I get about 3 months of run time on my original 4l setup. I expect to get about 6 weeks on this 2.5l setup. I bought bulk citric acid and baking soda here on Amazon and just keep it on hand for when I need to fill them back up. Over all, I highly recommend these kits. I will not hesitate to purchase more if I expand my tank collection. I'd like to see a 1l desktop setup so I can add CO2 to my nano tanks. I'd buy 3 immediately!
...
show more
Reviewed in the United States on December 12, 2025 by Dougie Fresh
Size: 5L
A good system with a few plastic parts. I've had problems getting the system to run correctly every day. When it works it works well with tiny bubbles as desired. It stopped working and I couldn't figure out why until I used a soapy water mixture to test the connections. The one way valve which is plastic was leaking air preventing it from working. I've ordered a new metal valve and hopefully it will fix my problems.
...
show more
Reviewed in the United States on March 19, 2026 by Sean
Size: 2.5L
Great system and super easy setup! The instructions are right there on the canister label so I don't have to look it up every time. This co2 system works wonderfully and is an accessible way to add CO2 to any aquarium. I have a few plants that require CO2 but all of the plants in general are loving it.
...
show more
Reviewed in the United States on July 11, 2026 by hootie huey
Size: 5L
Brought this CO2 tank couple months ago. Decided to set it up a month ago (big mistake for me to wait this long). Since day 1 the solenoid never operated correctly or at all. I believe its stuck in the on position. Tried some troubleshooting ive seen online but nothing worked. So I have to manually shut off and on the tank every day to ensure I don't overdose my tank. The set up itself is good and of great quality, But the solenoid issue makes this annoying and overshadowed the product. Tldr: Solenoid was sold to me defective.
...
show more
Reviewed in the United States on June 12, 2026 by Anon
Size: 2.5L
I am updating my old review. I liked the 2.5L so much I ended up buying a 5L. Another winner. I was able to set up the 5L version in 10 minutes. Very easy. Remember to find the sticker from the box. it has instructions on the forumla My PSI is nice and strong and the bubble counter is smooth. I am able to get it as low as 1 bubble per sec. Excellent product, well built. I already own two FZONE co2 regulators. The cost of CO2 was inching up - especially if you own multiple planted aquariums. After researching, I found this DIY kit. I am extremely impressed. Add 200 gms of citric acid and 200 gms of baking soda and 300 ml of water. A digital scale is nice. But you can always find an equivalent weight if you are eyeballing the measurement. Wait for an hour. The CO2 seems smooth. The bubbler works wonderful. Everything seems great. Check out the video
...
show more
Reviewed in the United States on December 2, 2025 by R. sankaran