3.4. Water quality parametersThere were no major differences found in the water qualityparameters of temperature, dissolved oxygen and pH between HSPand MSP at the beginning of the trial. However, significant dif-ferences (p < 0.05) were found between the ammonia and nitritecontent of water in HSP and MSP (Table 3). At the end of experiment,water temperature was considerably reduced due to entering thewinter season. However, other parameters were similar to those atthe beginning of the trial.