# Water Changes

In the context of maintaining a reef tank, a water change refers to the process of removing a portion of the water in the tank and replacing it with fresh, clean water. This is typically done to help maintain the water quality in the tank and provide the organisms in the tank with the essential nutrients and minerals they need to thrive.

Over time, organic matter, excess nutrients, and other waste products can build up in the water in a reef tank, which can lead to a range of issues, including poor water quality, algae blooms, and increased risk of disease. By performing regular water changes, reef tank owners can help to remove these built-up pollutants, dilute any excess nutrients, and replenish the essential minerals that are necessary for the health and growth of the organisms in the tank.

The frequency and volume of water changes required for a particular tank will depend on a range of factors, including the size of the tank, the number and types of organisms in the tank, and the level of biological activity in the tank. As a general rule, it is recommended that reef tank owners perform regular water changes of around 10-20% of the total volume of the tank on a weekly or bi-weekly basis.