Determining of water bioremediation dosage in recirculating water system for Cantik Grouper (Epinephelus fuscoguttatus × Epinephelus microdon) nurseries

Abstract The use of recirculating aquaculture system (RAS) in nurseries cantik grouper ( Epinephelus fuscoguttatus × microdon ) has the potential to make culture environment more stable and maximize production perfomance, but work RAS decreases with accumulation waste water used. Remediation microorganisms (bioremediation) can improve performance RAS. This research aims determine best dose commercial probiotics bioremediation be used seeds. was conducted for 7 days using a completely randomized design four treatments three replications. Treatment doses tried: 3 ml/m , 6 9 12 . container concrete tank measuring 1 m 2 0.8 filled seawater 3.2±0.3 cm seeds density 500 fish/m addition up mL/m had no significant effect (P>0.05) on survival rate fish rearing, ranging from 99.1% 99.3%. results process were obtained lowest range ammonia nitrite about 0.0896–0.9303 mg/L 0.0977–8.4880 mg/L. probiotic inhibit growth pathogenic bacteria such as Vibrio spp. at beginning, middle, end maintenance reached 2, 48, 140 CFU/mL.