How to Set Up an Aquarium CO2 System the Easy Way
For beginners, it is best to use slow-growing plants and low-lighting when starting a planted tank. Certain plants can be difficult to grow underwater. They may need more carbon dioxide (CO2) than what is naturally present in the air. 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 not the only primary ingredient that plants need in order to grow. Too much light and fertilizer is common among beginners. Adding CO2 to the aquarium can balance it. If a tank is over-lit or has too little fertilizer but not enough CO2 injection, algae can form.
As an example, let’s take a cookie recipe. To make a larger batch of cookies (e.g. greater plant growth), you should add 5x the normal amount of flour (e.g. fertilizer), to your dough. If you increase the flour by 5x and then add 5x more chocolate chips (e.g. CO2) to the recipe, it will cause bad results (e.g. algae growth).
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. The third group of plants, which includes Blyxa japonica and dwarf hairgrass and dwarf baby tears, is more demanding and requires CO2 to ensure success.
Materials for a CO2 System
This guide will focus on how to install the CO2 system, not lighting or fertilization. Get the tools and equipment you need to get 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’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 also helps to prevent “end-of-tank dumps,” in which a nearly empty CO2 cylinder may dump out the rest of its gas in one go. 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. 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 tank – Can I use a CO2 paintball cylinder? No, the Aquarium Co-Op regulator is not intended for use with paintball tanks. These regulators work with standard cylinder tanks with the male thread size CGA320. – Where can I buy a CO2 cylinder? We like to get ours from local home brewing supply stores and welding supply stores. They will usually offer refill services for empty cylinders. Which CO2 cylinder size should I choose? High-tech aquariums injected with large amounts of CO2 will require you to refill your cylinder more often. We recommend a 2.5-5 lb cylinder for our customers. cylinder for 20-gallon aquariums or smaller, a 5 lb. A 10 lb. cylinder is available for 25-to-40-gallon aquariums. cylinder for aquariums up to 55-gallon. You can use one regulator for five to six aquariums. If so, you will need to scale up the cylinder size.
1. Airline tubing or CO2 tubing – Do I need to use special CO2 proof tubing or CO2 resistant tubing? We use the Aquarium Co-Op airline tubing (i.e., a flexible, black tubing made from food-grade PVC) on all of our aquariums and have not detected any perceptible loss of CO2. Our experience shows that special CO2 tubing costs more, is harder to bend, and is not as easily available.
1. Regular check valve or stainless-steel check valve (optional). Do I require a CO2 regulator? Check valves prevent water from flowing out of your aquarium and pouring onto the regulator. The bubble counter in the Aquarium Co-Op regulator comes with a built-in check valve, but you can install a second one as backup if desired. 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. That being said, CO2 does degrade plastic after a very long time, so we also offer a stainless steel version for greater durability.
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? Because diffusers can be made of different materials, follow the manufacturer’s cleaning instructions to use diluted bleach, vinegar, or 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. However, the water will evaporate over time, so mineral oil can be used instead so you never have to refill the bubble counter.
Timer for electrical outlets 1. Adjustable wrench with at least 1.25-inch width 2. Scissors 3. Spray bottle with water, Dawn dish soap and a few drops
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 high-level diagram will help you see the whole CO2 system.
– The regulator (B) screws onto the CO2 cylinder (A). – 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 to the diffuser (D), which is placed at the bottom of the aquarium. 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 in to the electrical outlet timer H. This plugs into a power strip or wall outlet.
Is it bad if the CO2 bubbles from the diffuser are reaching the water surface? No, this is normal. Your diffuser should be placed as low as possible within the aquarium. As the bubbles rise from the diffuser, you can see them becoming smaller and smaller. The CO2 gas is being absorbed by the water.
Place the diffuser at the base of the aquarium to give the CO2 bubbles a longer time to dissolve into the water.
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. Also, we personally do not use drop checkers to chase the “perfect” amount of 30 ppm of CO2, but instead we let nature and the plants tell us when they are 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 the water is saturated in oxygen, aquatic plants produce visible bubbles.
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. (If you only have one timer, you can use the same timer with a power strip so that the light and regulator turn on and off at the same time.)
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. Hobbyists may try to reduce surface agitation in order to limit gas exchange and CO2 escape from 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. Use an air stone or other device to agitate the water surface in conjunction with your pressurized O2 system to increase CO2 and O2 levels. 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 all the best with your pressurized CO2 system. We also hope that you enjoy exploring the world high-tech plants. Check out our product page to find the official manual and demo video.