Goals of a Recirculating Filter System

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We define a reuse water filtration system simply as a filtration system that continuously filters the same water using all critical modes of filtering needed to sustain a healthy aquatic environment. Many things can alter water quality; however, most critical to environmental parameters are the concentrations of dissolved oxygen, ammonia-nitrogen, nitrite nitrogen and carbon dioxide in the water. Nitrate, pH and alkalinity levels are also important to your water's quality. Re-circulating filtration systems always combine various modes of filtering, each accomplishing its own unique task.

Achieving and Maintaining a Healthy Aquatic Environment

Are you a zookeeper or a koi hobbyist? Regardless of whether you are caring for a pair of river otters or a pool of colorful koi, water quality concerns you. It not only affects the esthetics of your pool, but also the health of your system's inhabitants. Accumulation of nitrogen is one of the most critical problems of a re-circulating "water re-use" system. Nitrogen in the system, commonly referred to as Total Ammonia-Nitrogen (TAN), is a by-product of protein metabolism. TAN is excreted from the gills of fish as they digest food and is produced when bacteria decomposes organic waste solids within the system. When the water in a system has a pH of about 7.0, the system is stable and the majority of TAN is ionized and does not adversely affect the system. But when a system has a pH of about 9.0, up to 30 percent of TAN may not be ionized and levels of ammonia-nitrogen can become extremely toxic to fish. Nitrite-nitrogen results from the oxidation of ammonia-nitrogen. When nitrifying bacteria (nitrosomonas) consume ammonia-nitrogen for energy, they produce nitrite-nitrogen as a by-product. Nitrite-nitrogen then binds with hemoglobin to form methemoglobin, which is not capable of binding and transporting oxygen. This ultimately suffocates the fish. In most cases re-circulating systems with mature nitrifying bacteria colonies should maintain nitrite-nitrogen concentrations below 1 mg/l. Fortunately, nitrobacter bacteria, also present within the system, use nitrite-nitrogen for energy and produce a much less harmful nitrate-nitrogen by-product. Nitrifying bacteria are the foundation of biological filtration and safely grow on all surfaces of the aquatic environment, including substrate, plumbing and the walls of the tank. Carbon dioxide can also accumulate in re-circulating systems as a by-product of fish and bacteria respiration. A well-designed re-circulating system should maintain adequate dissolved oxygen levels while minimizing carbon dioxide concentrations. "De-gassing" is a term, most commonly used within the aquaculture industry, to best describe stripping carbon dioxide from water. De-gassing is a simple procedure that involves aerating water that is low in oxygen, removing carbon dioxide, and at the same time, increasing dissolved oxygen levels. Packed media columns, venturi air injectors or moving-bed bio filters can accomplish the same results. When selecting a life support system, it is best to establish which filtering method best suits your application's style, size and most importantly, the needs of its inhabitants.

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UV Sterilizer and Filter Products for Koi Ponds & Water Gardens:
Pond UV Sterilizers and Filters. EmperorAquatics-Pond.com

UV Sterilizer and Filter Products for Fresh & Saltwater Aquariums:
Aquarium UV Sterilizers and Filters. EmperorAquatics-Aquarium.com

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Your Investment is in the Water... We Protect It!

Achieving and Maintaining a Healthy Aquatic Environment