In a recirculating aquaculture system the culture water is purified and reused continuously. A recirculating aquaculture system is an almost completely closed circuit. The produced waste products; solid waste, ammonium and CO2, are either removed or converted into non-toxic products by the system components. The purified water is subsequently saturated with oxygen and returned to the fish tanks. By recirculating the culture water, the water and energy requirements are limited to an absolute minimum. It is however not possible to design a fully closed recirculating system. The non-degradable waste products must be removed and evaporated water must be replaced. Still our recirculating systems are capable of reusing 90% or more of the culture water. To ensure good water purification, recirculating systems consist of a number of components with specific functions. See detailed explanation on RAS technology below. Both system are perfectly capable of removing the ammonia from the system water. The choice of biological filtration is depending on many factors (e.g. available space, outside temperature, energy costs, etc.)