pH Test Kits and Alkalinity Test Kits
pH test kits may test only the range that is relevant to certain freshwater or saltwater environments, so make sure you get the right one. Significant pH changes are fatal, and can be prevented with stable alkalinity (also affected by GH & KH). Regular use of pH and alkalinity test kits is the only way to spot trends and problems that need to be immediately addressed.
pH varies slightly over time; we recommend testing at the same time of day, every 2 weeks or more frequently if establishing a new tank. When bringing home new fish, compare the pH of its old water to yours, and slowly acclimate it to its new habitat.