Water level control of small-scale recirculating aquaculture system with protein skimmer using fuzzy logic controller

The recirculating aquaculture system (RAS) is a land-based facility, either open-air or indoors, that minimizes water consumption by filtering, adapting, and reusing water. Solid organic matter from fish waste food directly becomes needs to be eliminated because it source of increasing total ammonia nitrogen (TAN), suspended solids (TSS), dissolved (TDS), also has an impact on reducing oxygen (DO). RAS requires level control so the tank does not experience shortages floods, disrupting aquatic ecosystem. In this study, small-scale modeled using 3-coupled tanks approach with configuration follows most straightforward recirculation process (fish tank, mechanic filter, biofilter). Clean reservoir flows into through protein skimmer. This study applies fuzzy logic controller (FLC) in skimmer biofilter controlling position several valves where placement positions have been determined according requirements. results show tuned single-input FLC best average output response characteristics t<sub>s</sub>=50, h<sub>1ss</sub>=49.98, e<sub>ss</sub>=0.02 t<sub>s</sub>=4700, h<sub>1ss</sub>=39.75, e<sub>ss</sub>=0.25 system.