Environmental pH and Supplemental C Exert Little Impact on Shrimp, but Profound Impacts on Plants in Marine Aquaponics

pH is the major factor that makes producers in aquaponics frustrated, since the main three organisms (aquatic animal, plant, and microbes) in the system with different preferences. Yet, amending the growing environment with additional C is a potential method to improve the growth of shrimp and plants as well as the establishment of microbe. A detailed study of the effects of pH and additional C on aquaponics under saline conditions has not been investigated. In this study, the effect of pH and additional C on the growth performance of shrimp (Litopenaeus vannamei) and five edible plants in marine aquaponic systems using the nutrient film technique (NFT) was evaluated. The results indicated that at both pH 6.5 treatments, plants grew better; nevertheless, the growth performance of plants in pH 7.5 with additional C was improved and showed a similar yield to lower pH treatments. On the other hand, shrimp growth was little affected by pH and additional C. A higher impact of imbalanced ionic composition on shrimp performance may have contributed to this trend. Hence, we suggest that only if the ionic composition is managed can make RO water a suitable source of water for shrimp-based aquaponic. In spite of this, more research is required.