| Alkalinity: The capacity of water to resist changes in pH which is measured by the concentration of carbonates. Alkalinity is increased by the addition of carbonate buffers such as sodium carbonate. |
| Buffer: A substance which contains carbonate and increases the alkalinity (carbonate concentration) of the water. |
| pH: A measurement of acidity or basicity of water, with 7.0 being neutral. The pH tolerance of fish varies from species to species. Fish such as goldfish and koi generally adapt to the pH of local waters but it is important to not make rapid changes in pH. The shock of rapidly fluctuating pH can stress or even kill fish. Pond pH generally follows a daily cycle of being lowest just before dawn and highest in the afternoon due to photosynthesis and aquatic life respiration. pH increases with plant population and decreases with excessive organic matter and animal population. Low pH water can harm fish gills. High pH water can harm fins and gills and contribute to unwanted algae growth. |