The evaluation of an ozone purification system in a recirculating aquaculture system

An Ozone Purification System (OPS, Robert B. Hill Co., Minneapolis, MN) was evaluated to determine its potential as a reconditioning agent for the water within an intensive culture system using original cross hybrid striped bass. In the first of two 36-day trials, two stocking densities (3.5 g/L (1X)), and 7.1 g/L (2X)) in the recirculating systems were compared to a 3.5 g/L (1X) stocking rate in the typical flow through system (i.e., the water is only used once). At stocking, mean weight and length per system averaged 11.6 g / 100 mm, 12.6 g / 102 mm, and 11.2 g / 101 mm for the flow-through system and single and double density systems, respectively. Final weights ranged from 33.8 g in the flow-through system to 30.0 g in the single density system and 21.8 g in the double density system. The second trial evaluated only the recirculating systems using stocking densities of 4.8 g/L (1X) and 9.5 g/L (2X). Stocking measurements for the 1X system were 34.0 g and 135 mm and 34.0 g and 137 mm for the 2X system. Final weights were 47.5 g and 44.0 g for the 1X and 2X systems, respectively. A photoperiod was kept on a 12 hour dark/12 hour light cycle during the study. An economic analysis on the cost effectiveness of use the Ozone Purification System within the recirculating system was significantly more effective at growing fish than the flow-though system stocked at the same density.