Freshwater Planted Aquariums: CO2 Systems for Healthy Planted Aquariums View Cart You may change your account settings, including your Billing & Shipping Addresses, Credit Card Information, as well as Express Checkout status.
  Welcome to!  
HOME    HELP    CONTACT US    MY ACCOUNT    SIGN IN - Quality Aquatic Life Direct To Your Door. - Quality Aquatic Life Direct To Your Door.

Diver's Den - WYSIWYG Fish, Corals, Inverts & More
Weekly Specials

Freshwater Fish Pond Foods Freshwater Plants Freshwater Inverts Aquarium Supplies
Marine Fish Coral Reef Rock Reef Cleaner Packs Marine Invert/Plant ORA Fish/Coral/Inv

CO2 Systems for Healthy Planted Aquariums

Introduction to CO2 Systems

The two basic requirements for healthy aquarium plants are light and proper carbon dioxide (CO2) levels. Through a process called "photosynthesis," aquarium plants use light energy and CO2 to produce food necessary for lush growth. As plants develop, they use up their existing supply of carbon dioxide. Installing a CO2 system is essential to prevent low CO2 levels and to maintain active plant growth. These systems are available in three basic styles to ensure a healthy environment for planted aquariums of all sizes.

Manual CO2 Systems
Most manual CO2 systems are essentially yeast fermentation systems. CO2 is generated as a metabolic byproduct of yeast and stored within a fermentation canister. The accumulated carbon dioxide travels through a reaction chamber and is then mixed with the aquarium water by means of a diffuser or a powerhead. These systems are easy to use, budget-friendly, and well suited for smaller planted aquariums. Just as their name implies, these units must be turned on and off manually to maintain ideal CO2 levels within your aquarium.

Semi-automatic CO2 Systems
Semi-automatic CO2 systems involve a bit more effort to install initially, but are timer-operated to help simplify CO2 injection. A CO2 canister supplies carbon dioxide and the amount of CO2 entering the aquarium is controlled by a series of components, including a pressure regulator with solenoid, a bubble counter, and a CO2 diffuser. The timer-operated solenoid opens during a set period of time (i.e. when the lights are on) to supply plants with carbon dioxide. These systems are perfect for mid-size and larger planted aquariums that have a greater demand for CO2.

Examples of Semi-automatic Systems:

Do I need a CO2 system for my planted aquarium?
CO2 supplementation is usually contingent upon light intensity. In general, heavily planted aquariums with high output light fixtures will require a CO2 system to keep up with the greater plant demand for carbon dioxide.

Automatic CO2 Systems
Automatic CO2 systems share many of the same features as semi-automatic systems. The main difference is the addition of a pH controller and probe. This high tech upgrade constantly monitors aquarium pH. When the pH probe detects the pH level falling below the set point, the pH controller automatically shuts off the flow of CO2. These automatic systems simplify CO2 supplementation in aquariums of all sizes but their benefits shine in large systems or heavily planted aquariums that require a steady supply of CO2.

Example of a fully automatic system:

No matter which style of CO2 system you employ, it is important to routinely monitor aquarium pH and CO2 levels. Excess CO2 can create conditions harmful to fish including low oxygen levels and drops in aquarium pH.

Related Articles
Tips for a Successful Freshwater Planted Aquarium
Dosing Planted Aquarium Nutrients
Caring for Your Live Plant Aquarium


Click here for a more printer-friendly version of this article.   Click here for a PDF version of this article.   Bookmark and Share


Up to 40% OFF DEALS! Subscribe today »
Contact Us
Shipping Rates
Shipping Schedule
How to Order
Track Your Order
Rewards Program
Diver's Den Help
Gift Certificates
Business Partner Program
Email Newsletters
PayPal Credit     PayPal®
WI Facility Open Houses
Invasive Species
About Us
Who We Are
Aquatics Specialists
Customer Comments
100% Guarantee
Visit our other sites:
Twitter YouTube Instagram
Freshwater Fish   |   Pond Fish & Plants   |   Brackish Fish   |   Freshwater Inverts   |   Freshwater Plants
Marine Fish   |   Corals   |   Reef Rock   |   Tank Cleaners   |   Marine Inverts   |   Marine Plants   |   Supplies
Visit our Retail Store   |   Site Map
bizrate Customer Certified Site - Reviews at Bizrate Drs. Foster & Smith BBB Business Review McAfee Secure sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
*FREE SHIPPING on qualifying aquatic life orders $99 and up. FREE SHIPPING on qualifying aquarium supplies orders $19 and up. Excludes Frozen Foods. See details

Copyright © 2017, Doctors Foster and Smith. All rights reserved.
2253 Air Park Road, P.O. Box 100, Rhinelander, Wisconsin 54501..
Updated 11/09/17: Terms of Use  |   Privacy Policy