Water chemistry Water is the growing environment for fish, so a reliable source of good quality water is vital to fish farming. Pond chemistry is very complicated and many factors can be changed by adding specific chemicals. Some parameters such as salinity, alkalinity, and calcium content are not easily changed by chemicals. If the water source does not contain these three properties a lot of time and energy must be applied to maintaining the fish farm. This process involves taking up ions and excreting water through membranes.
Salinity also affects other constituents such as dissolved oxygen and ammonia concentrations.
Alkalinity greater than or equal to 20 ppm also traps CO2 and increases the amount available for photosynthesis. Pond alkalinities for catfish should fall between 55 to 400 ppm. Calcium cations are essential for bone and scale formation, as well as other metabolic processes. Financial aspects Farmers can choose from surface water from lakes and streams, or well water. Surface water is usually much cheaper but may contain predator species and pathogens.