In an ecological system, it is natural for carbon dioxide (CO2) and oxygen (O2) to work hand in hand. Whether the ecosystem is on land or in water, these two gases coexist. As the amount of one gas increases, the amount of the other decreases.

At sunrise, the oxygen levels in the fish pond or water garden are at their lowest. This is due to processes that occur in the pond at night. As the sun rises, the oxygen begins to recover its levels. As soon as the sun goes down, carbon dioxide levels in the pond begin to rise until dawn the next day. This is an ongoing process that makes the pond more prone to algae blooms at night.

Having a UVC (ultraviolet clarifier) ​​or UV sterilizer will help prevent CO2 from eventually taking over your pond and causing the suspended algae to grow more. If there is too much algae in the pond, don’t expect the fish to survive for another year or less.

Having the right pond aerator will also help maintain the balance of oxygen and carbon dioxide in the pond. What the aerator will do is circulate oxygen easily throughout your water system, distributing it evenly so that no living creature is left short. That way, when CO2 levels rise at night, you won’t overload the oxygen as much.

Carbon dioxide, like algae, is a natural part of a certain pond. However, if its quantity increases excessively, that is the time when it becomes fatal. This gas enters the pond through the process of photosynthesis in plants and algae and through respiration in creatures such as fish and invertebrates. In addition, CO2 can come from the decomposition of organic matter on the pond bed, such as leaves, tree branches, uneaten food, fish waste, and decaying algae. O2 and CO2 are equally important to each other. However, if too much CO2 accumulates more than O2, the lives in the pond will be at stake since O2 is what they breathe. And if there is more CO2 than O2, there is an undeniable possibility that algae will form blooms. Algae are plant-like creatures that survive through photosynthesis. They consume CO2 which is why it is more dangerous for a pond at night.

If one day you find yourself looking at your pond with most of the fish floating around dead, there is a good chance that things have happened during the time that you were not able to check the water system. One is that some predatory animals like cats or birds have attacked and killed the fish. The other is the presence of too much algae that you obviously didn’t notice was blooming. For algal blooms to occur, an excessive abundance of CO2 and extremely low levels of O2 are required.

Note that the amount of CO2 is higher in hot seasons and O2, on the other hand, is higher in cold seasons. But still, CO2 has a higher chance of overcoming the pond because O2 can only be produced in the presence of sunlight.