3.1. System setup (Fig. 1)
Raft aquaponics can be the most simple and least cost aquaponics
system. The essential elements of an aquaponic system as
suggested by Rakocy et al. (2006) are fish-rearing tanks, a settleable
and suspended solids removal component, a biofilter, a hydroponic
component and a sump. In raft aquaponics if the plant and its
supporting media such as gravel and coarse sand can provide sufficient
biofiltration, a separate biofilter is not needed (Rakocy et al.,
2006). Solids removal component is highly recommended by
Rakocy et al. (2006) since if otherwise the organic materials from
fish fecal waste and unconsumed feed accumulate, deposit and
decompose anaerobically in tank bottom, the reduced toxic products
can deteriorate water and harm the fish. In our system, the
upwelling afloat from disk membrane diffuser kept the solids