Whether you're doing a reef tank, fish-only saltwater aquarium or any other marine system, recording and logging your levels is of utmost importance. Keeping tracking of your water parameters is an important step in maintaining healthy, thriving saltwater fish and corals.This 8.5"x11" log book helps you track the most important levels: temperature, PH, ammonia, nitrites, nitrates, phosphates, magnesium, alkalinity, calcium and more! Makes a great gift for reef hobbyists and other aquarium lovers. Contains 100 pages. Each page contains a chart with 7 days of parameters.