Treatment NH4-Na NO2-Na NO3-Na PO4-Pa pH T Alka Chl aa SSa TSSa
1.4 kg/m3                  
    Initial 1.01 0.02 0.00 7.85 8.7 217.1 661.8 3 105.4
    Final 0.02 0.03 94.91 23.58 7.5 84.4 1,694.0 57 667.8
    Pooled SE 0.38 0.01 5.54 0.63 0.0 4.5 197.9 1 16.5
    Pr > F 0.139 0.671 0.007 0.002 0.002 < 0.001 0.026 < 0.001 < 0.001
2.1 kg/m3                  
    Initial 0.84 0.03 0.00 8.32 8.7 214.1 675.9 4 114.8
    Final 0.02 0.02 112.60 28.35 7.3 76.8 1,471.5 75 760.0
    Pooled SE 0.37 0.01 11.51 2.01 0.1 4.4 231.0 7 41.4
    Pr > F 0.260 0.895 0.020 0.002 < 0.001 < 0.001 0.072 0.002 0.005
2.8 kg/m3                  
    Initial 0.41 0.03 0.00 7.48 8.7 218.4 602.8 4 102.2
    Final 0.02 0.03 130.88 32.67 7.3 81.6 1,048.2 68 753.3
    Pooled SE 0.14 0.01 6.45 0.70 0.1 6.8 234.9 1 25.0
    Pr > F 0.128 0.982 0.005 < 0.001 < 0.001 0.002 0.251 < 0.001 < 0.001
a Total ammonia nitrogen (mg/L NH4-N), nitrite-nitrogen (mg/L NO2-N), nitrate-nitrogen (mg/L NO3-N), soluble reactive phosphorus (mg/L PO4-P), total alkalinity (mg/L as CaCO3 T Alk), chlorophyll a (mg/m3 Chl a), settleable solids (mL/L SS), and total suspended solids (mg/L TSS).
Table 2: Within treatment comparison of least squares mean (± SE) initial and final water quality variable concentrations for outdoor biofloc technology tanks stocked with large (217 g/fish) channel catfish at 1.4–2.8 kg/m3.
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