PH Levels in Aquariums & Ponds

The measurement of acidity and alkalinity is called pH. The H stands for yydrogen. It is not known what the "p" stands for, though scientists say it stands for potential, power or potency. The scale for measuring pH is between 1 and 14, with 1 the most acidic; 7, neutral; and 14, the most alkaline.

  1. Importance

    • In aquariums, pH is an indicator of water quality. Inconsistent pH levels create stress in aquarium or pond inhabitants.

    Changing pH

    • If pH is too low, add a commercial alkaline buffer. If pH is too high, identify the cause for the high pH, address the cause and then use peat or commercial pH decreasing chemicals. For example, hard water and increased algae growth can raise pH levels. Using reverse osmosis water provides a better water source with fewer minerals. And optimizing temperature and light sources slows algae growth.

    pH in Freshwater Aquariums

    • Freshwater aquariums should have a pH between 6.5 and 7.5, according to Doctors Foster and Smith. Some freshwater species, such as discus and cichlids, have more specific pH requirements.

    pH in Saltwater Aquariums

    • Saltwater habitats run slightly more alkaline than freshwater, with an acceptable range between 7.8 and 8.3. "The Marine Aquarium Handbook" says the ideal pH level is 8.2.

    pH in Ponds

    • The optimal pH for ponds to encourage survival and growth is between 6 and 9. Because of natural conditions, pH in ponds varies throughout the day. The lowest pH level occurs in the morning. Throughout the day, pH rises as carbon dioxide is removed from the water through photosynthesis.