water quality
Over the course of the trial, TAN, DO and pH levels remained within acceptable ranges in all replicates. Observed TAN concentrations did not exceed 0.30 mg/L and were ofuen below the detection limit (0.02 mg/L), indicating quick and efficient nitrification by the bacterial biofilter. Among all replicates, observations of Do concentration varied between 8.18 saturation varied between 80.0 and 94,4 indicating that adequate was achieved by the continuous falling action of water. Finally, pH aeration levels each replicate o the course of the trial from slightly gradually declined in near-neutral values at the end of alkaline values early in the trial between 7.99 and 8.33) to water the trial (between 6.94 and 7.44). The high calcium carbonate content of replacement ph). likely provided buffering capacity. For each of the above parameters (TAN, DO and no significant differences were observed between feed treatments (p o.05) results NO2-N concentrations were assumed to be negligible, and the concentration from the EPA-114-A Rev. 9 detection method were attributed solely to No N. Across all replicates, concentrations of NO-N showed a generally increasing trend over the course of the trial from of 19.0 mg/L on day 13 to an average of 15.0 mg/L on day 60 based on average source and normalized data, NoyN normalized data (Fig. 2). Based on both concentrations under the fishmeal-based feed treatment were significantly higher than PO4-P concentrations also generally increased across all replicates o the course of the trial, from an average of 0.33 m on day 18 to an average of 0.89 on day 60 based normalized data (Fig. 3 Although the mean of observed POATP concentrations on concentrations were was greater under the alternative treatment than under the control, the trial (p 0.142 and between treatments over the course of the 0.150 for source data and normalized data, respectively)