The experiment was conducted at the Aquaculture Research
Facility of the Asian Institute of Technology, Thailand (13.06◦N
latitude and 100.62◦E longitude at an altitude of 2.7 m). A 2×3 factorial
design consisting of pond water filtration as the first factor,
versus unfiltered pond water, and three different growth media
as the second factor, i.e. the control treatment (2cm thick 1m2
styrofoam sheet), gravel (2.5cm in size) and builders’ grade sand
(0.1–0.25mmin size), were used in this study. There were six treatments
in triplicate: (A) unfiltered pond water and styrofoam sheet;
(B) unfiltered pond water and gravel; (C) unfiltered pond water and
sand; (D) filtered pond water and styrofoam sheet; (E) filtered pond
water and gravel; (F) filtered pond water and sand.