What is an Overflow Aquarium?

An overflow aquarium is a type of aquarium that has an overflow box built into it, which allows water to overflow from the main tank into a separate compartment, called a sump. The sump is usually located under the aquarium, and it serves as a place to house equipment such as a protein skimmer, a heater, a chiller and other filtration methods.


The overflow box is designed to allow water to flow over the top of the tank and into the sump. This happens when the water level in the tank reaches the top of the overflow box, the water flows through the box and into the sump where it is then pumped back into the tank. This allows for a constant water flow and circulation, promoting better water quality and oxygenation.

The use of a sump allows for a more efficient and effective filtration system, as well as more stable water level in the main tank, which can be useful when the equipment in the tank, such as protein skimmer and heater, use up a small amount of water and cause the water level in the main tank to drop.

The main benefit of an overflow aquarium is the increase in water movement and oxygenation, which helps to keep the water in the aquarium clean and clear, reduce the fish waste and other organic matter, and improve the overall health and well-being of the fish and other aquatic life in the tank. The use of a sump allows for more equipment and filtration options, which also improves the water quality.

Overflow aquariums can be more complex than other types of aquariums, as they require a little more maintenance, such as keeping the overflow box and the sump clean, and sometimes require a certain level of skill to properly set it up and maintain it.