The effectiveness of using biofilter with addition of activated charcoal on the growth of red lettuce (Lactuca sativa var. crispa) and tilapia (Oreochromis niloticus) in the aquaponic system

Fishery is an agricultural sub-sector that plays a very important role in the development of the national economy. Fishery resources in Indonesia are very diverse and have the potential that include fish farming. Fish farming aims to produce higher biomass compared to natural fishing. Aquaponics is a cultivation technology that combines the maintenance of fish and plants that are more environmentally friendly and conserves water use. Aquaponics can reduce the accumulation of ammonia, nitrate and nitrite by fish feed residues and fish metabolism with plants and biofilter media to absorb these compounds. Tests were carried out with two installations with different components, namely bioball and activated charcoal (1:1) and control with only bioball components. Testing the effectiveness of the biofilter component was carried out by conducting research designs, preparing tools and materials, cultivation processes, observing and collecting data on red lettuce plant growth, red lettuce plant biomass productivity, tilapia growth, water quality, environmental conditions and data processing and analysis. It was found that the effect of adding activated charcoal biofilter media on the growth of leaf number and chlorophyll content was different, with better average results in activated charcoal installations (1:1), but lower growth in plant height, leaf width, and leaf area (p< 0.05). The growth of leaf area and chlorophyll content affected the treatment position as indicated by the best leaf area at position 8, while the best chlorophyll content was in treatment 2. The addition of activated charcoal biofilter media to dry weight was significantly different (p<0.05) better in the activated charcoal installation compared to the control installation, but with a lower Shoot-Root Ratio. Activated charcoal installation (1:1) also shows better average fish growth with more fish survival and better water quality maintenance.