Effect of Different Aquaponic Systems and Presence of Volcanic Stone Filtering Material on Nutrient Concentration in Water and Geranium Growth

Aquaponics combines hydroponic cultivation and aquaculture, where water quality is a primary consideration for both plant growth and fish health.In many cases, the filtering material is helpful tool to maintain and optimize water quality for plant and fish.The objective of this study was to investigate the effect of different types of aquaponic systems and the presence of volcanic stone as a filtering material on the water quality and the growth of geranium pot flower plants.Goldfish was used.The experiment was held in a controlled environment for six weeks, and three types of aquaponic systems were used: deep water culture (D), modified deep water culture (M), and nutrient film technique (N).Each type of system had two different settings, based on the presence of the volcanic stone filtering material (V).Hence, a total of six different treatments, D 0 , D V , M 0 , M V , N 0 , and N V , were used, where 0 and V indicate the absence and presence of volcanic stones in an aquaponic system, respectively.The results showed that NH 4 + and NO 3 -concentrations of aquaponic water were increased in all treatments compared to their initial stage.After the treatment period, the concentrations of NO 3 -and K + were higher in D 0 , M 0 , and N 0 treatments compared to those where volcanic stones were present (D V , M V , and N V ).However, after the treatment period, Ca 2+ ions showed decreased concentration compared with their initial stage in all treatments, except M 0 and M V .The EC level steadily increased in all treatments over time; at six weeks after treatment, it was around 0.4 dSm -1 in all treatments.However, pH fluctuated during the treatment period.At six weeks after treatment, the plant height, leaf length, leaf width, and SPAD value of geranium plants were not significantly affected by the presence of volcanic stone in different types of aquaponic systems (D, M, and N).Nevertheless, the leaf area of the geranium was higher in N 0 and N V treatments than in the others.Furthermore, total root length, total root surface area, and the number of root tips were higher in N V -treated plants.In addition, principal component analysis (PCA) analysis showed that the maximum growth parameters of plant responses were closer to the N 0 and N V treatments.These results suggest that comparatively, treatment N V is preferable for maintaining sustainable water quality and the growth of geranium plants in an aquaponic system.