All about C02 in the aquarium

What is Co2 in the aquarium? What is the purpose of Co2 in the aquarium? How to diffuse Co2 in the aquarium ? Injecting carbon dioxide into the aquarium has several advantages. In fact, Co2 is used to lower the pH of the water, to improve the growth of the aquarium plants and above all to fight against algae. If you are planning to use an aquarium Co2 system, this guide will explain how to use CO2 in your planted aquarium.

The functions of CO2 in the aquarium

CO2 is an essential element in the growth of aquarium plants, so you must be careful to control its level to ensure that your plants have a constant amount in the water. Of course CO2 is not the only element to monitor in your aquarium, it is only one of the key elements for success.

CO2 is one of the many substances that plants need to assimilate on a daily basis in order to grow well. Plants need light adapted to their needs, so they will be able to convert carbon into carbohydrates through photosynthesis. Generally speaking, CO2 is injected into the aquarium because plants are carbon-consuming species and oxygen producers, which is very important for the animal species in the aquarium. Inserting plants into an aquarium increases the level of CO2, thus meeting the needs of the plants to allow them to grow further. And as the quantity of plants increases, the quantity of oxygen follows the same logic, which guarantees a good oxygenation of the aquarium.

The advantage of this technique of bringing oxygen into your aquarium by the plants, compared to an injection of air into the water, is a lower oxygen loss, since the oxygen that is produced by the plants is directly dissolved in the water.

The CO2 kits for aquarium, how to choose?

There are different ways to inject CO2 into your aquarium. The most common injection systems are composed of a compressed carbon dioxide bottle, with different capacities, accompanied by a diffuser or a reactor. Some studies show that diffusers are less efficient than reactors, as their output is relatively lower. One of the reasons is that with the reactor, water and gas are mixed inside a tube before being released. Whereas the diffuser releases the gas directly into the water.

There are several types of kits:

Fermentation kit
It is not advisable to lower the pH because it is not constant. It is very difficult with this kit to have a stable pH level. Being therefore very variable, and difficult to adjust, it is not recommended for constant use. However, it is widely used to help plants to grow.

Kit under pressure with disposable bottle
With this kit you can have a stable CO2 level in your aquarium. The amount of carbon dioxide can be adjusted as you wish, so you can adapt the level to the needs of your aquarium. The main users recommend this kit to complete the fertilization of a planted tank or to lower the pH level.

Refillable bottle pressure kit
Unlike the previous kit, this one uses refillable bottles. The CO2 injection is always constant and adjustable. Being very modifiable, and adapting quickly, it allows to complete the fertilization of a planted tank but also to contribute to the decrease of the pH.

Another piece of advice, the place for your CO2 diffuser is important. If possible, place it as far as possible from the pump’s circulation. By moving it away from the filter, you ensure a good diffusion of the CO2, otherwise it would be absorbed as soon as it is diffused.

Craft CO2 distributor

Alternatively, you can make your own CO2 dispenser. This solution is more economical and fairly easy to implement. It can be used as a complement of a kit, rare are the people who only use this system. For the creation of this there are different systems of CO2 production.

We find the system of different immersed solutions, such as a mixture of sugar and yeast that will cause the formation of alcohol accompanied by the release of carbon dioxide. And it is the latter that will be injected directly from the aquarium.

Or another system of carbon dioxide injection which consists of using a bell. This technique is used to create fine bubbles that will dissolve more easily in water. Two solutions are available to you, buy a bell in the trade, or make it yourself. One way is to use a small transparent container fixed above the diffuser. This last technique allows you to provide the plants with the ideal quantity they need for their development, neither more nor less CO2. However, the use of a home-made CO2 diffuser is not recommended when starting up your aquarium.

In general, it is advisable to automate the injection systems by an electronic PH-meter that controls the flow of CO2 injected. This will allow your aquarium to adapt to the different variations that there may be, for example at night the CO2 needs are much lower so it will not be necessary to inject CO2. This adjustment in real time, will allow you to have a balanced ecosystem on a daily basis.