Abstrak
Water quality is one of the primary factors influencing the success of shrimp aquaculture, as it supports optimal growth. Conversely, due to the accumulation of toxic compounds, poor water quality negatively affects shrimp health and can ultimately result in mortality. This study aimed to analyze water quality in traditional black tiger shrimp (Penaeus monodon) ponds on Tibi Island, Bulungan Regency. Sampling points were determined using purposive sampling across two pond plots-one measuring 1.3 hectares and the other 6 hectares. Water samples were collected from three points with three replications in each pond. Treatments included using probiotics: EM4 was applied three times in the smaller pond, and "Rica" treatment in the larger pond. Sampling was conducted monthly throughout the seeding, maintenance, and harvesting periods. Both physical and chemical parameters were measured. In the small pond, water temperature ranged from 28 31.67 °C, pH 5.87-7.27, dissolved oxygen 6.47-7 mg/L, salinity 9.67-17 ppt, ammonia 0.1-1.2 mg/., nitrite 0.03-0.42 mg/L, nitrate 0.3-0.61 mg/L, phosphate 0.04 0.05 mg/L, and alkalinity 13.33-80 mg/L. In the large pond, water temperature ranged from 29.9-32.03 °C, pH 5-7.4, dissolved oxygen 6.8 6.87 mg/L, salinity 10-15.33 ppt, ammonia 0.1-1.14 mg/L, nitrite 0.10 0.22 mg/L, nitrate 0.3-0.41 mg/L, phosphate 0.05 0.13 mg/L, and alkalinity 11.67-88.33 mg/L. The small pond treated with EM4 showed relatively better water quality. Several parameters did not meet the quality standards of the Indonesian Ministry of Marine Affairs and Fisheries Regulation No. 75/2016, including pH, ammonia, nitrate, nitrite, and alkalinity in the small pond, and pH, ammonia, nitrite, phosphate, and alkalinity in the large pond. Other parameters were within acceptable limits.