How to Set Up an Aquarium CO2 System the Easy Way
We encourage newbies to plant tanks with slow-growing plants. They only require low light and an all-in one fertilizer. However, certain plants are a little more difficult to grow underwater and may require high lighting and extra carbon dioxide (CO2) beyond what is naturally provided in the air. Aquarists can inject CO2 gas directly into water using many methods. They have tried many types of equipment, scheduling and dosage amounts. Aquarium Co-Op has tested many of them, and this is our preferred method. It’s reliable and simple to use.
Does CO2 eliminate algae? Many people believe that CO2 will solve algae problems. A healthy tank should have three components: lighting, fertilizer and carbon dioxide. CO2 is only one of the essential nutrients plants require to grow. Many beginners use too much light and fertilizer, so adding CO2 can help balance the aquarium. If a tank is over-lit or has too little fertilizer but not enough CO2 injection, algae can form.
Let’s use a cookie recipe as an analogy. If you add 5x the usual amount of flour (e.g., fertilizer) to your dough, then you must also multiply the rest of the ingredients (e.g., lighting and CO2) by 5x, which will result in a bigger batch of cookies (e.g., greater plant growth). However, if you add 5x the amount of flour and then try to “balance” the recipe by only adding 5x the amount of chocolate chips (e.g., CO2), the rest of the ingredients are not in the correct ratio and will result in a bad cookie (e.g., algae growth).
Does every aquarium plant require CO2 injection? All aquatic plants use CO2 for their basic building blocks. Cryptocoryne plants are one example of a type that doesn’t require extra CO2, but other types such as scarlet temple, which could benefit from it, don’t. A third category of plants – which includes Blyxa japonica, dwarf hairgrass, and dwarf baby tears and other similar carpeting plants – has higher demands and necessitates the use of CO2 for the best chances of success.
Materials for a CO2 Systems
In this guide, we are focusing on the installation of the CO2 system and not the lighting and fertilization components. To get started, gather the necessary equipment and tools:
1. Aquarium Co-Op CO2 regulator What’s a regulator? It is a device that controls how much CO2 exits the CO2 cylinder tank into the aquarium water. What’s the difference between a single stage and a two-stage regulator? A one-stage regulator lowers the gas pressure in the cylinder in one step. However, a two-stage regulator lowers the pressure in two, which results in a more reliable and stable flow of CO2. A two-stage regulator helps prevent “end of tank dumps,” which is when a nearly empty CO2 container may release all its gas in one shot. Which CO2 system should I choose? While DIY systems are cheaper than pressurized systems, they don’t have the same stability as a CO2 system that uses a regulator and/or cylinder. DIY reactions produce lots of CO2 initially, then slowly decrease in quality over time. This can make it difficult to balance a plant tank. Additionally, the process is slower because of the low pressure and temperature. We can set it up once, and it will run for one- to three years before we have to refill it.
1. Aquarium Co-Op manifold-block add-ons (optional). With our regulator you can install up five additional manifold-block add-ons in order to expand your system and run CO2 into multiple tanks.
1. CO2 cylinder tank Can I use my CO2 paintball tube? The Aquarium Co-Op regulator was not designed for paintball tanks. They work with standard cylinder tanks that have the male thread size CGA320. Where do I get a CO2 Cylinder? We prefer to buy ours at local home brewing supply shops and welding supply shops. Usually, they also offer CO2 refill services if you bring back your cylinder when it’s empty. – What size CO2 cylinder should I get? If you are running a high tech planted aquarium injected with high amounts of CO2, people recommend getting the largest size possible so you will not have to refill the cylinder as frequently. For the average customer, however, we recommend a 2.5-5lb. cylinder for 20-gallon aquariums and smaller. A 5 lb. A 10 lb. cylinder is available for 25-to-40-gallon aquariums. cylinder for aquariums up to 55-gallon. Scale the cylinder to fit five or six aquariums.
1. Airline tubing, or CO2 tubing, is it necessary? We have never seen any CO2 loss in our aquariums using the Aquarium Co-Op airline tube (a flexible, black, PVC-based tubing) from Aquarium Co-Op. In our experience, special CO2 tubing is more expensive, harder to bend, and not as readily available.
1. Regular check valve, stainless steel check valve (optional). Do you need a check valve to protect my CO2 system from water escaping the tank and pouring over the regulator after it is turned off? The Aquarium Cooperative regulator has a built in check valve. However, you can also add another one to provide additional protection. We have personally used the regular plastic check valves with CO2 systems at our fish store, warehouse, and homes, and they have not broken down. However, plastic can be degraded by CO2 over time so we offer stainless steel versions for better durability.
1. CO2 diffuser Which CO2 diffuser type should I choose? All CO2 diffusers designed for aquariums should operate at around 40-50 psi. What can I do to clean a CO2 diffuser that has become clogged with algae? Different materials can make diffusers, so follow the manufacturer’s cleaning instructions. Use diluted bleach, vinegar, and other methods.
1. Mineral oil or water – You can use regular tap water to fill the bubble count so you can determine the rate at which CO2 enters the aquarium. The water will eventually evaporate so mineral oil is an alternative.
An electrical outlet timer Adjustable wrench with at least 1.25-inch width 2. Scissors Spray bottle with water and a few drops of Dawn dish soap
How to Install a Co2 System
Once you have the necessary equipment, we recommend that you read our detailed manual and watch the video tutorial to learn how to use it. This diagram shows the connections between all parts of the CO2 system.
The regulator (B), which screws onto the CO2 tube (A), is shown in Figure 1. – Optional manifold block add-ons can be added to the regulator (B). The bubble counter (C), located on the regulator, is filled with liquid. An airline tubing attachment is made to the bubble counter’s lid. The airline tubing connects directly to the diffuser, which is located at the bottom. – The optional check valve (E) is installed in line with the airline tubing near the aquarium rim. The power adapter (G) connects to the regulator’s solenoid cable (F). The power adapter, (G), plugs in to the electrical outlet timer H. This plugs into a power strip or wall outlet.
What if the CO2 bubbles emitted from the diffuser get into the aquarium’s water surface? This is normal. Your diffuser should be placed as low as possible within the aquarium. The bubbles released from the diffuser will imperceptibly shrink as they rise, and the CO2 gas is being absorbed in the water.
Place the diffuser at base of aquarium to allow the CO2 bubbles to disintegrate in the water for a longer period.
How Much CO2 to Dose
In the manual, we recommend tuning the regulator to approximately 1 bubble per second (i.e., the rate of CO2 bubbles flowing through the bubble counter) because we would rather start with a lighter amount of CO2 to keep the fish safe. That being said, CO2 dosing amounts are different for every tank, and the bubble rate is not a perfect form of measurement since each aquarium has different plant and fish stocking levels. Drop checkers are not used to achieve the ideal CO2 concentration, as we prefer to let the plants and nature tell us when they feel happy.
When the plants photosynthesizing during the daytime, they consume carbon dioxide and produce oxygen (O2) and sugars as a byproduct.
If plants have enough carbon dioxide and light, they can produce enough oxygen to saturate the water. This is visible as small bubbles appearing from the leaves. In our warehouse, we dial the CO2 level on our plant-holding aquariums until we consistently see this “pearling” effect. Plants are living things and it takes around 24 hours for any CO2 adjustment to have an effect. We like to wait three days before we make the next change.
Aquatic plants “pearl” or visibly produce bubbles when the water is saturated with oxygen.
When should I turn on and off the CO2 in my aquarium? As mentioned before, plants use CO2 when there is light to photosynthesize. However, the process reverses at night and becomes the respiration cycle, in which plants consume oxygen and sugars and release CO2. Therefore, we want to shut off the CO2 regulator when the aquarium light is off. To optimize CO2 use, set the regulator’s timer so that it turns on about 1-2 hours before the aquarium light comes on. The regulator will then turn off approximately 1 hour before the light goes out. You can also use a single timer to control the light and the regulator simultaneously.
Is CO2 dangerous for aquarium fish? It can be harmful for animals in large enough quantities if (1) CO2 causes the water pH to drop too quickly or (2) people try to be so efficient with the CO2 that they end up cutting off the oxygen that fish need to breathe. In the latter case, some hobbyists try to minimize surface agitation so that less gas exchange occurs and less CO2 escapes the water. However, less gas exchange also means less oxygen will enter the water, which can cause your fish to struggle and gasp for air. We recommend increasing both O2 and CO2 in the water using an airstone (or any other device that agitates water) along with your pressurized carbon dioxide system. Yes, you may have to increase your bubble rate a little to compensate for the slight loss of CO2, but having enough oxygen for your fish (and plants at night) is more important and can help lead to the pearling effect that is so desired by planted tank enthusiasts.
We wish you the best with your new pressurized carbon dioxide system. We hope you have lots of fun exploring high-tech plants. You can find more information about our CO2 regulator on the product page. There is a demo video and a manual.