How to Set Up an Aquarium CO2 System the Easy Way
When it comes to planted tanks, we always encourage beginners to start with easy, slow-growing plants that only need low lighting and an all-in-one fertilizer. Some plants may be more difficult to grow under water and will require additional carbon dioxide (CO2) and high lighting. Aquarists have used many different methods, equipments, schedules, dosages and techniques to inject CO2 gas into their water. Aquarium Co-Op has tried many and created this guide to help you choose the most reliable and simple method.
Can CO2 be used to get rid of algae? This is a common misconception. A healthy planted tank must have three components in balance – lighting, fertilizer, and carbon dioxide. CO2 is just one of the primary nutrients that plants need to grow. Too much light and fertilizer is common among beginners. Adding CO2 to the aquarium can balance it. Algae can develop if there is too much fertilizer or high lighting in a tank.
Let’s use a cookie recipe as an analogy. You can increase the flour by adding 5x more (e.g. fertilizer) to the dough. Then you will need to multiply the other ingredients (e.g. lighting and CO2) by 5x. This will produce a larger batch of cookies, which will lead to greater plant growth. You can make a bad cookie if you only add 5x as much flour to your recipe.
Does every aquarium plant require CO2 injection? All aquatic plants use CO2 for their basic building blocks. Some types like cryptocoryne plants do not need the extra CO2, while other plants like scarlet temple could benefit from it but don’t require it. Blyxa japonica is a third type of plant that requires more CO2. This includes dwarf hairgrass, dwarf baby tears, and other carpeting plants.
Materials for a CO2 System
This guide will focus on how to install the CO2 system, not lighting or fertilization. Gather the required equipment and tools to get you started.
1. Aquarium Co-Op CO2 regulator – What is a regulator? A regulator is a device that allows you to precisely control how much gas exits the CO2 cylinder tank and enters the aquarium water. What are the differences between a single-stage and two-stage regulators? A single stage regulator reduces cylinder’s gas pressure by one step. A two-stage regulator decreases the pressure by two steps. This results in a more stable, reliable flow of CO2. Two-stage regulators are also better at preventing “end-of tank dumps,” where a CO2 cylinder that is nearly empty may leak its remaining gas in one step. Is it better to use a DIY or pressurized CO2? We’ve tested many DIY systems that contain yeast and citric acid. However, they are less stable than a pressurized CO2 system with a regulator/cylinder. DIY reactions can produce a lot of CO2 in the beginning, but then decrease over time. It can also make it difficult for a tank to be balanced due to inconsistent CO2 levels. Additionally, the process is slower because of the low pressure and temperature. A pressurized system is easy to set up and run for one to three decades before refilling the cylinder.
1. Aquarium Co-Op manifold block add-ons (optional) – With our regulator, you can install up to five extra manifold blocks add-ons to expand the system and run CO2 to multiple tanks.
1. CO2 cylinder tanks – Is it possible to use a CO2 paintball tank? 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 or smaller, a 5 lb. A 10 lb. cylinder is available for 25-to-40-gallon aquariums. cylinder for 55-gallon aquariums or larger. You can use one regulator for five to six aquariums. If so, you will need to scale up the cylinder size.
1. What is the difference between airline tubing and CO2 tubing? We use Aquarium Co.Op’s flexible black PVC tubing on all our aquariums. There has been no perceptible CO2 loss. 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. We also offer a stainless-steel version to increase durability, but CO2 can degrade plastic over time.
1. CO2 diffuser What type of CO2 diffuser should you get? A CO2 diffuser that is designed for aquariums operating at 40-50 PSI should work fine. 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 Dawn dish soap
How to Install a Co2 System
After you have everything you need, you can follow our video tutorial and detailed manual for step-by-step instructions. To help you visualize the entire CO2 system, this high-level diagram shows how all the parts are connected:
The regulator (B), screws onto the CO2 tank (A). The regulator (B) can have optional manifold blocks added. 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 with the diffuser (D), which can be found at the bottom. The optional check valve, (E), is installed along with the airline tubing at the aquarium rim. The regulator’s solenoid vale cable (F), is connected to the adapter (G). The power adapter (G), plugs into the electrical outlet (H), which plugs into either a wall outlet, or power strip.
Is it bad if the CO2 bubbles from the diffuser are reaching the water surface? No, this is normal. The key is to place your diffuser as low as possible in the aquarium. The bubbles released from the diffuser will imperceptibly shrink as they rise, and the CO2 gas is being absorbed in the water.
Put the diffuser in the aquarium’s base to give the CO2 bubbles more time to dissolve into water.
How much CO2 should you consume?
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.
The plants can produce enough oxygen if they have enough light and carbon dioxide. You can see tiny bubbles bursting from their leaves if this happens. In our warehouse, we dial the CO2 level on our plant-holding aquariums until we consistently see this “pearling” effect. Because plants are living things, it usually takes at least 24 hours after we adjust the CO2 to see any effect, so we like to wait three days before making the next change to the system.
When water is saturated with oxygen, aquatic plants can produce bubbles or “pearl”, which are visible to the naked eye.
When should I turn on and off the CO2 in my aquarium? As mentioned before, plants use CO2 when there is light to photosynthesize. The process is reversed at night, and the respiration cycle takes place, where plants use oxygen and sugars to produce 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. Our recommendation is to increase both CO2 and O2 in the water by using an air stone (or other device that agitates the water surface) in conjunction with your pressurized CO2 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.
Best of luck with your new pressurized CO2 system and we hope you have fun exploring the world of high tech plants. You can find more information about our CO2 regulator on the product page. There is a demo video and a manual.
