Book excerpt: Written by an expert on marine biology, this title is must reading for the marine aquarium hobbyist. Keeping ocean-dwelling fish and other marine life forms thriving in the synthetic environment of an aquarium requires special knowledge and care, especially in regard to water quality. The author discusses the properties of natural seawater, then gives details on how to create and maintain high-quality synthetic seawater. He describes biochemical cycles and fluctuating conditions that are normal in a flourishing marine aquarium, instructs on adding needed chemical components, and advises on water analysis test kits, instrumentation, and record keeping. Includes illustrations plus informative tables and charts.