The system was governed by the principle of "one-pump rule" where culture water was recirculated by a 40-watt pump in a closed loop. The design prevented the system from failure and collapse since only one pump lifted the water from the bio-filtration tank, the lowest section, to the fish tank, the highest section, and allowing water to flow by gravity along the raceway and return pipe network and back to the bio-filtration tank. The system generated good water quality having 5.6 parts per million average dissolved oxygen at 100 per cent average saturation and 21.4 C average temperature with...