WHY a lot of tiny bubbles from sand bed could be seen in a fish tank

Why a lot of tiny bubbles from the sand bed could be seen in a fish tank


Aquariums are a great way to enjoy nature, but they can also be a source of stress for many people. The immense responsibility of caring for the fish and keeping the water clean can be overwhelming. That’s why it’s important to understand how to maintain your aquarium properly, and what you should do if something goes wrong. This goes true as well with artificial ponds having fish or with aquaculture tanks. Good bacteria in OZPOLISH Bio-Cure for aquariums or Ornamental Fish Farms/ Outdoor Fishponds play an important role in completing the nitrogen cycle of the fish tank.

Importance of the Nitrogen Cycle in Aquariums:

The nitrogen cycle is one of the most essential parts of maintaining a healthy aquarium. This cycle consists of ammonia, nitrite, nitrate, and finally, nitrogen and water. It is necessary for bacteria to break down waste in a tank and turn it into harmless substances that don’t harm the fish, or other aquatic plants and animals. If this process isn’t completed correctly, it can lead to problems with both the water quality and the health of the tank dwellers.


Why a lot of tiny bubbles from the sand bed could be seen in a fish tank

The Role of Bacteria in the Nitrogen Cycle:

The last stage of the nitrogen cycle is the only one that we can see in an aquarium, a pond, or an aquaculture tank. The process starts with a fish or plant releasing ammonia, through wastes, into the water. The ammonia is then converted by bacteria into nitrite and then nitrate. When these compounds reach a certain level, they are released from the substrate and bubble out into the water column. The process is commonly called as nitrogen cycle in a fish tank.

The Problem with Assuming a Tank is Cycled:

The problem with this process is that people assume that once their tank cycles, it will stay cycled because they can see bubbles coming out of their substrate. This isn’t true because as soon as more fish or plants are added to the tank, more ammonia will be released and a cycle may start all over again. This tank would then need to have the beneficial bacteria count maintained. This is common in heavily populated tanks, such as in the case of the Malawi Cichlid Aquarium.  Nitrosomonas is a nitrifying bacteria that convert ammonia into nitrite, Nitrobacter is yet another nitrifying bacteria that convert nitrite to nitrate. Nitrifying bacteria require oxygen as well as a high pH. Denitrifying bacteria are responsible for reducing nitrates into nitrogen gas. They prefer to use DO (dissolved oxygen) and need a low pH level. To accomplish the task of converting nitrate to nitrogen gas, would need tank water with low dissolved oxygen. In such a situation, instead of oxygen, they have to consume nitrate. Other than nitrifying and denitrifying bacteria, other forms of bacteria are those that treat organic wastes such as leftover solid food, sludge, etc. There are a bunch of different types of Organic Waste Decomposing Bacteria. Usually, the bottom-most portion of the sand bed has low water flow, and so has low DO. The denitrifying bacteria would work here to potentially convert nitrate to nitrogen. Once achieved, this could be seen in the form of a lot of tiny bubbles when the sand is shuffled.

Using Plants and Live Rock to Reduce Nitrate Levels:

If the tank doesn’t have a sand bed, alternatively plants can be used in freshwater tanks to reduce nitrate levels. They are an excellent way to create a natural environment and they provide oxygen for the fish. In saltwater aquariums, live rock can reduce the nitrate level. Live rocks and deep sand beds are important because they help maintain pH levels, provide a natural environment, and create hiding places for the fish.

The Importance of Organic Waste Decomposing Bacteria:

Nevertheless, tanks would still essentially need all the nitrifying, denitrifying, and organic waste-decomposing bacteria. The organic waste-decomposing bacteria are necessary for the nitrifying or denitrifying bacteria to work efficiently. If the bacteria input contains specific enzymes, it simply could boost up the entire process. This is what happens in the tank with the application of OZPOLISH Bio-Cure Advance, These are the guys that make a tank habitable for all those fish being loved by their owners. They are so miraculous that they are capable of converting all the visible organic wastes eventually to nitrogen gas, and that is done without the use of any synthetic chemical. This is the way nature works in rivers, lakes, streams, and seas from where the fish originally belonged to. Nitrogen gas is harmless for the known fact that the earth’s atmosphere is made up of 78% nitrogen. A healthy tank will often have an earthy smell, like the scent of fresh mud after rain. Even if you see bubbles coming out of the substrate, there’s usually no need to worry. In fact, these can be signs that your tank is thriving!

When Bubbles from a Tank Bed Are a Concern:

Though, in general, bubbles from a tank bed are a natural indicator of a healthy aquarium, it is a matter of concern or could really be a serious issue if these bubbles have a bad smell, like pungent or rotten egg. It could be as serious as the release of trapped poisonous gasses (such as Hydrogen Sulphide, H2S) and need to be tackled immediately. It is commonly seen that the bubbles formed due to harmful gasses are bigger. It may be toxic if the bubbles are dark brown/grey in colour. To make sure it doesn’t happen it is a best practice to do weekly swishing through the sand. This will release the bubbles before they become toxic.


Aquariums and artificial ponds with fish can provide a beautiful and relaxing environment to enjoy nature. However, proper care and maintenance are crucial to ensure the health and well-being of the fish and other aquatic life. Understanding the nitrogen cycle and the importance of beneficial bacteria can help aquarium owners maintain a healthy tank. Products such as OZPOLISH Bio-Cure Advance can assist in maintaining a balanced ecosystem by converting organic waste to nitrogen gas. Regular maintenance, including monitoring water quality and removing excess organic waste, is essential to prevent issues such as ammonia spikes and toxic gas buildup. By following these guidelines, aquarium owners can create a thriving aquatic environment for their fish and enjoy the beauty of nature in their homes.

Explained: Why a lot of tiny bubbles from sand bed could be seen in a fish tank

Related Topic: WHY need OZPOLISH Bio-Cure, when Nitrobacter and Nitrosomonas grow naturally on its own, establishing the nitrogen cycle in 2 months

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