It is recommended that DO levels be maintained at 5 ppm or higher in aquaponics systems. They will come to the surface for oxygen-rich surface water if DO levels go down to 1 ppm. Tilapia are tolerant of lower levels of DO, but growth rates will be affected. Warmwater fish (e.g., bass, bluegill, and catfish) require about 5 ppm (ppm or parts per million, which can be used interchangeably with milligrams per liter ) and coldwater fish (e.g., trout) require about 6.5 ppm of DO to maintain good health and maximum growth. Dissolved Oxygenĭissolved oxygen (DO) is one of the most important parameters for growing fish and is also critical to the beneficial nitrifying bacteria that convert fish waste into nutrients plants can use. Keeping good records of your water quality measurements can help greatly in observing trends and diagnosing future problems. In all cases, it is important to record all of your readings. Once nutrient cycles are balanced, weekly testing is usually sufficient. For example, in response to high ammonia levels, feeding levels can be reduced, aeration can be increased, or water can be diluted. However, as a general rule, start-up systems should be tested daily so that adjustments can be made quickly when needed. Testing frequency will vary depending on the parameter being monitored. Whatever source of water is used, it is very important to have it tested and to obtain a water quality profile to ensure that it meets the requirements to grow fish and plants. Municipal water is treated with chlorine and chloramines, which must be removed before it can be used. Surface water is not recommended because of the difficulty in ensuring consistency in water quality due to risk of contamination. Potential sources include well water, municipal water, and surface water. Selecting the source of water used in an aquaponics system can greatly influence the water quality, and is an important first consideration. For additional information on water chemistry, refer to NMSU Extension Guide W-104, Understanding Water Quality Parameters to Better Manage Your Pond ( ) Source Water A good understanding of how these parameters interact with each other is necessary in order to maintain a balanced system. This guide describes the most important water quality parameters that affect the health and productivity of aquaponics systems.
For more basic information on aquaponics, refer to NMSU Extension Guide H-170, Is Aquaponics Right For You? ( )īecause this system combines plants with animal production, it has a special set of water chemistry requirements, and optimal water quality is essential to a healthy, balanced, functioning system. Aquaponics combines the cultivation of both fish and plants into a recirculating ecosystem that utilizes natural nitrifying bacteria to convert fish wastes into plant nutrients. ( Print friendly PDF) IntroductionĪquaponics, a method of food production that combines fish farming with soilless plant production, is growing in popularity and gaining attention as an important and more sustainable method of growing food. Important Water Quality Parameters in Aquaponics SystemsĬollege of Agricultural, Consumer and Environmental Sciences, New Mexico State UniversityĪuthor: Extension Aquatic Ecology Specialist, Department of Extension Animal Sciences and Natural Resources, New Mexico State University.