Why must aquarium water be free of sewage and industrial pollutants?

Maintaining high water quality is the primary requirement for the health of aquatic organisms in an aquarium. Water must be free of sewage and industrial pollutants because these substances introduce toxic chemicals, pathogens, and excess nutrients that degrade the environment and threaten the survival of the specimens.12

Specifically, pollutants impact the aquarium environment in the following ways:

• Toxicity and Disease: Industrial wastes often contain heavy metals and toxic chemicals that can directly poison aquatic life. Domestic sewage introduces pathogenic microorganisms that pose significant health risks and can lead to outbreaks of disease within the tank.13
• Oxygen Depletion: Organic matter from sewage promotes the growth of algae. As this organic material and algae decompose, microorganisms consume the dissolved oxygen in the water, leading to conditions where fish and other aerobic organisms struggle to survive.13
• Chemical Imbalance: Industrial pollutants can interfere with the delicate chemical balance required for aquatic life, including the necessary gaseous equilibrium with the atmosphere.12

To ensure a safe habitat, water supplies must be purified to remove such contaminants, and recirculating systems must be carefully managed to treat metabolic wastes.2