Aquarium CO2 Regulator: Complete Buying Guide

Just as people and virtually all the other animals in the world need oxygen to live, plants also need carbon dioxide (CO2) in much the same way. But that can be a problem in a planted tank unless you put in a CO2 system. So you’ll need to buy one, and they’re available as separate parts or as a complete CO2 kit.

Benefits of a CO2 Regulator

What happens when the CO2 level in your tank goes too low?

Factors to Consider when Buying a CO2 Regulator

So now that we know what to look for, let’s check out some top regulator options.


1. AQUATEK CO2 Regulator Mini

Now this kit comes with most of your CO2 needs. It requires a paintball CO2 tank, and you don’t need an adaptor to connect.

It’s also compatible with most CO2 diffusers and atomizers. All these parts aren’t part of your purchase.

A bubble counter is also included, and it comes with an integrated check valve. While you can always replace it with 3rd party parts, they’re still nice to have as backup.​


  • The use of the paintball CO2 tank means you won’t have to settle for the large industrial-sized tanks that admittedly are kind of ugly.
  • There’s really no need for assembly.
  • You get a nice “cool touch” industrial solenoid design that’s easy to use. You can hook this up to the timer.
  • You can fine tune the release of the CO2, with the precision needle valve.
  • As it is “mini”, it’s not too big so you can easily hide it from view.
  • The gauges are easy to read.
  • The customer service people are helpful, according to those who are still within their 90-day warranty.


  • It only uses paintball CO2 tanks, so you’re limited to 24-ounce tanks. If you have a large tank, this can result in frequent refilling for the tank. Fortunately, CO2 tanks are cheaper to refill.
  • Turning the needle valve is a bit finicky, as it’s so sensitive.
  • Some have complained of catastrophic failures after 2 years (or even 8 months). So every time you refill the tank, you may want to replace the O-ring.

2. U.P. Aqua CO2 Regulator for Aquarium

This regulator is made from heavy duty brass, and it comes with an electronic solenoid and a high precision needle valve.

It also uses the CGA320 Connector. It features an adjustable working pressure and there’s a decompress pressure valve.


  • This you can use with larger 20-pound CO2 tanks for 35-gallon aquariums.
  • The assembly instructions are easy to follow, and there’s really nothing to it.
  • It’s also easy to use.


  • It may need some sort of break in period (especially the solenoid) before it works smoothly.
  • It’s a bit picky with the bubble counter and diffuser options. It can use the Atomic Bubble Counter and Atomic Diffuser.

3. Pro CO2 Regulator Hydroponics Aquarium

Now this is the cheapest of the regulators on this list. Yet you can go online and find lots of rave reviews about it. It’s also made of brass and it comes with an industrial solenoid valve.

However, you must understand that this is actually meant for green houses and indoor gardening styles such as hydroponics.


  • It can be used for an aquarium, however. You can use it with a 10-pound CO2 tank. Some of the rave reviews did come from aquarium owners.
  • The setup is very easy. Attach the regulator to the tank and to the diffuser, and then power it up.
  • The tooling is high quality, so you won’t need to use tape to guard against leaks.


  • It does concern some people that it was not specifically designed for aquarium use.
  • Some people have noticed a humming sound, but it’s very slight.

4. Red Sea Fish Pharm Aquarium CO2 Standard Pro System Plant Care

This is complete kit, meant for aquariums in sizes ranging from 10 to 125 gallons.

Your purchase includes the CO2 regulator, reactor 500, a high precision inline needle valve, and a bubble counter with integrated check valve. It also features a real-time CO2 monitor and you also get CO2 tubing.


  • It’s great for those looking for an all-in-one solution (aside from the CO2 cylinder, which it needs).
  • It works with paintball CO2 tanks.
  • Since you get a reactor, you don’t need a diffuser.
  • It works like a skimmer, so you don’t need a solenoid. But you need to run it constantly.
  • It can work with very large aquariums.


  • The price is high, and it might costs more than double of the other regulators on this list.

My Pick

I’m still concerned about the Pro CO2 Regulator when used in aquariums, though it does seem like a viable and very affordable option. But the all-in-one Red Sea Fish Pharm System might seem overpriced.

For me, I’ll pick the AQUATEK CO2 Regulator Mini for small tanks, and the U.P. Aqua CO2 Regulator for the bigger tanks.

What are your picks? Write in your comments and tell us how your regulator compares.

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