2. Materials and methods
2.1. Aquaponic system
Aquaponic is a special form of recirculating aquaculture systems (RAS), namely a polyculture consisting of fish tanks (aquaculture) and plantsthat are cultivated in the same water circle (hydroponic) [3–5]. The primary goal of aquaponic is to reuse the nutrients released by fishes to grow crop plants. Most systems separate fish faeces as
quickly as possible to reduce the BOD load in the RAS, to enhance nitrification performance and to reduce clogging of plant roots, which could lead to loss of crop productivity.