How does an open aquarium water system control toxic wastes?

In an open aquarium system, toxic metabolic wastes are controlled by the continuous flow of water through the enclosure. Because the water flows through the aquarium once and is subsequently discarded, there is no buildup of these wastes, allowing the system to maintain water quality comparable to that of a natural environment.1

While this method effectively prevents the accumulation of toxins, it is important to note that open systems often require filtration and can be costly due to the expenses associated with pumping and maintaining appropriate water temperatures.1