Water quality was monitored daily for dissolved oxygen (DO), temperature, pH, and
bi-weekly for ammonia-N, total alkalinity, hardness, total phosphate, and plankton
biomass following APHA (1989) methods. The means, standard errors, and ranges of the
water quality parameters were as follows: DO (06:OO h) 2.5 f 0.3 (0.6-6.3) mg 1-l; DO
(18:OO h) 6.2 + 0.7 (1.8-10.6) mg 1-l; pH 7.5 + 0.2 (6.7-10.4); temperature 29 f 0.3
(25-32) “C; ammonia-N 0.62 + 0.1 (0.01-2.03) mg 1-l; alkalinity 128 L- 5 (53-160) mg
1-l; hardness 143 + 5 (137-205) mg l- ’ ; total phosphate 0.25 + 0.2 (0.05-0.59) mg l- ’ ;
and plankton biomass 7 f 3 (l-26)mg 1-l.