## 3 Results
### Off-Flavors  
The concentrations of off-flavors GSM and MIB ranged from 2 to 8 ng/L (GSM) and from 13 to 36 ng/L (MIB) in water (Table 6). GSM concentrations decreased significantly during the experiment for hydroponics and aquaponics DWC (Table 6) but did not differ for RAS and aquaponics fish tank water (Table 6). In the case of MIB, the concentrations increased slightly during the experiment, excluding the hydroponic DWC water but without statistical significance (Table 6). MIB was 9.5 ng/L in the inlet water, while GSM remained below the limit of detection (<LOD). The concentrations of GSM were significantly lower (\(p\) < 0.05) in fish muscle grown in aquaponics compared to fish grown in RAS (Table 6). The concentration of GSM decreased (\(p\) < 0.05) in fish muscle after six weeks for the fish grown in aquaponics (Table 6). GSM and MIB were also detected in the shoots and roots of the spinach both in aquaponics and hydroponics in the start and after six weeks of the experiment. The concentrations of both GSM and MIB decreased in the shoots of both systems (\(p\) < 0.05) and in the roots of spinach grown in hydroponics (MIB \(p\) < 0.001) after six weeks (Table 7). In roots, however, the concentrations of GSM and MIB increased during the experiment for the aquaponics treatment, but without significant difference (\(p\) > 0.05, Table 7). While comparing between treatments, the MIB in shoots and GSM in roots for aquaponics were statistically higher than in hydroponics (Table 7). \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Off-Flavors**}} & \multicolumn{3}{c}{**Aquaponics**} & \multicolumn{3}{c}{**Hydroponics (DWC) or RAS**} \\ \cline{2-9}  & \multicolumn{2}{c}{**Start**} & \multicolumn{2}{c}{**End**} & \multicolumn{2}{c}{**Start**} & \multicolumn{2}{c}{**End**} \\ \hline GSM DWC & 5.60 & \(\pm\)1.60 & 3.62 & \(\pm\)1.37 \({}^{\text{A}}\) & 6.88 & \(\pm\)1.49 & 3.72 & \(\pm\)2.52 \({}^{\text{A}}\) \\ MIB DWC & 13.08 & \(\pm\)2.70 & 21.05 & \(\pm\)14.83 & 23.81 & \(\pm\)3.83 & 17.07 & \(\pm\)9.64 \\ GSM Tank & 6.29 & \(\pm\)3.13 & 7.97 & \(\pm\)1.29 & 6.62 & \(\pm\)2.50 & 4.97 & \(\pm\)2.82 \\ MIB Tank & 24.32 & \(\pm\)2.35 & 36.21 & \(\pm\)13.35 & 20.77 & \(\pm\)8.56 & 28.28 & \(\pm\)4.83 \\ GSM Muscle & 493.6 & \(\pm\)99.10 & 376.0 & \(\pm\)24.99 \({}^{\text{A}}\) & 493.6 & \(\pm\)99.10 & 466.3 & \(\pm\)39.40 \({}^{\text{A}}\) \\ MIB Muscle & 1758.1 & \(\pm\)298.5 & 1611.5 & \(\pm\)298.6 & 1758.1 & \(\pm\)298.5 & 1473.8 & \(\pm\)240.3 \\ \hline \hline \end{tabular} Values are means \(\pm\) SD, \(n\) = 3 for end samples and 2 for start samples. The superscript letter \({}^{\text{A}\rightarrow\text{A}}\) indicates statistically significant difference (\(p\) < 0.05) between the sampling points and \({}^{\text{A}\rightarrow\text{A}}\) between the treatments (aquaponics vs. RAS).  
\end{table} 
Table 6: Concentrations of off-flavor geosmin (GSM ng/L) and 2-methylisobromeol (MIB ng/L) in water from deep water culture (DWC) hydroponics (no fish tanks) and aquaponics (with baby spinach and rainbow trout), and water from fish tanks (aquaponics and RAS), and in rainbow trout muscle (ng/kg) (aquaponics and RAS) in the beginning (5 May) and at the end (14 June) of the 6-week experiment.