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What Are The Best CO2 Levels For An Aquarium

Carbon dioxide (CO2) is the single most vital nutrient for plants growth. In fact, it constitutes 50% of a plant mass. Therefore, a low level of CO2 in your aquarium water will reduce the growth of plants in it. The benefits of adding CO2 in planted aquarium has become very popular among aquarists.  CO2art is dedicated to providing their customers with convenient kits as well as to meet the rising demand.

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However, injecting the gas into the tank is not a simple case where you just add as much as possible. This gas is too much deadly to your fish when overdosed. You should thus monitor or test the level of gas levels of carbon dioxide in your tank using a CO2 Regulator. This will help you to fertilize your plants adequately and not to endanger your fish. 


Sources of CO2 in planted aquariums


  • The surrounding air through Gas exchange at the water surface 
  • Respiration by the life in the water such as fish as well as the plants when not lit.
  • Deliberate injection of CO2 to encourage plant growth


The best CO2 levels in planted aquariums


Fish do not flourish in high levels of CO2. Concentrations of CO2 above 30-35mg/l are indeed toxic to most aquarium lives. By ensuring proper setting of your aquarium, you reduce the problem of excess CO2. Such a problem can only occur in a good set-up tank if the gas fertilization results to an overdose. 

However, the gas may build up to a dangerous level in an over-stocked tank with poor water circulation, even without the addition of extra CO2. This mostly happens at night when the oxygen use is high along with more released CO2; watch out when you see fish gasping at the surface.


Therefore, you can only keep both fish and plants happy in the same aquarium by balancing the carbon dioxide necessities of the plants with the maximums of fish. By managing the concentration of CO2, you ensure a healthy ecosystem in your aquariums.


Determining the CO2 level


You can measure the amount of carbon dioxide in your aquarium water by testing both the KH (carbonate hardness) levels and the pH. You can then use the results to evaluate the concentration of the gas. You need to get the standard reference table and then cross-reference the two values, and their intersection gives the CO2 levels in your tank in mg/liter. 


The best safe levels of the gas for plant growth are between 15 mg/l and 35mg/l. If your tank uses mature or peat aquariums with a lot of debris and organic matter, then this method is not accurate. 


Aquarists also use other CO2 Regulators such as drop checkers and CO2 constancy devices to monitor CO2 levels. For this case, you measure pH fluctuations by employing a calibrated tracking fluid that works by changing color when the levels of CO2 changes. Since you install them permanently in your aquarium, you will get an at-a- glance reading of CO2. You will see a blue color if there is too little, a green color if the CO2 level is optimal and a yellow color if there is excess CO2.