Evaluation of Nutrient Flow Through and Media‐Bed Aquaponic Systems

ABSTRACT This study evaluates the performance of an integrated aquaponic system combining gravel bed and NFT modules within a recirculating loop, focusing on nutrient dynamics, plant growth and sensory quality. Conducted in a semi‐controlled greenhouse, the system utilized Nile tilapia ( Oreochromis niloticus ) and cultivated lettuce, Swiss chard and pepper. Water quality analysis showed reduced nitrate levels after the NFT module (0.792 mg/L) compared to source RAS water (1.04 mg/L), while the gravel bed demonstrated superior phosphate removal (0.052 mg/L) and the lowest ammonia concentration (0.074 mg/L). Lettuce grown in NFT exhibited significantly greater shoot biomass (187.00 ± 15.53 g) than gravel‐grown plants (105.33 ± 11.79 g), with similar differences observed in root biomass. Plant performance was significantly influenced by the cultivation system, plant variety and their interaction. Pepper plants in NFT produced more fruits (9.00 ± 1.47 vs. 5.50 ± 0.96) and longer fruits, while gravel‐grown fruits had ∼8% greater average mass, although this difference was not statistically significant. Sensory evaluation indicated a general preference for NFT‐grown lettuce in appearance, aroma, texture, flavour and overall acceptability, though these differences were not statistically significant. Economically, the NFT system yielded higher returns and lower media costs, resulting in a net financial benefit of 11,804.52 ETB. Overall, the NFT system outperformed the gravel bed in plant productivity, nutrient efficiency and economic viability, while gravel beds may offer advantages in contexts requiring greater phosphate or ammonia retention.