The Complete Handbook of Aquarium Water Treatments

Chapter 1: Understanding Aquarium Water Treatments

Understanding Aquarium Water Treatments

Aquarium water treatment is not a single product but a category of chemistry applied to a specific goal: making the water in your tank match the needs of its inhabitants. In practical terms, this means taking the water that comes from your tap, well, or municipal supply, and altering or conditioning it so that it is not immediately lethal to fish, and then maintaining conditions that allow biological and chemical processes to run correctly. The treatment is not a substitute for filtration, but it is the bridge between what comes out of the faucet and what can safely go into a glass box full of living animals.

Most tap water, especially in urban and suburban areas, is treated at a municipal plant with chlorine or chloramine to kill bacteria and pathogens. These disinfectants are effective at making water safe for human consumption, but they are toxic to fish. Chlorine burns the delicate tissue of a fish's gills. Chloramine, a compound of chlorine and ammonia, is a slower-acting but more persistent poison. A serious hobbyist cannot just fill a tank and turn on the filter. They must first render the water safe. This is the most basic and important job of a water treatment: dechlorination. A good dechlorinator doesn't just mask the problem; it chemically reduces the chlorine molecule, breaking it down into harmless chloride ions, or it breaks the chloramine molecule apart, neutralizing the chlorine and binding the freed ammonia