Each of plant growth bed unit and fish-rearing tank had 10 air
diffusers (2 L min−1), which were cleaned monthly. There were also
three air diffusers in the degassing tank. Settleable solids were
removed from the clarifiers one time daily by opening a ball valve.
Fine solids were collected by netting plastic screens in the filter
tanks and were removed two times monthly by draining the tank
and washing the netting. There was also a plastic screen at the
entrance of degassing tank which prevented fish fry to reach to
the hydroponic tank.