Water Quality Water quality factors of temperature, pH, alkalinity, hardness, and dissolved oxygen affect fish health and production. These factors are rarely constant in a pond. Temperature, dissolved oxygen, and pH will change or cycle each day, and alkalinity can change over longer periods of time. Oxygen dissolves into the pond water from the air as the two are mixed together through wind and wave action. Mechanical aeration using pumps, sprayers, and paddle wheels can be used to increase dissolved oxygen levels during periods of low oxygen.
Photosynthesis is the other source of dissolved oxygen.
In this process, plants produce oxygen while making food from carbon dioxide and water in the presence of sunlight. Algae release this oxygen directly into the water during photosynthesis. Since photosynthesis is driven by the energy of sunlight, oxygen production occurs during daylight. Therefore, dissolved oxygen concentrations in ponds tend to rise throughout the day. At night dissolved oxygen slowly declines as fish, insects, zooplankton, bacteria, and algae consume oxygen through respiration.