Figure 3.1. Main features of the 70,000 L re-circulating, barramundi broodstock tank. Water is drawn from the main drain, filtered through a rapid sand filter and then passed by an Ultra-Violet lamp. From there it is heated or cooled through a reverse cycle heat exchanger and then on through a carbon filter to reduce the organic content. Ammonia and nitrite are removed using a fluidised bed biofilter and the water gravity feeds back to the tank through a de-gassing column. More organic material in the water is removed using a separate foam fractionation unit. New, UV treated sea water is added at the rate of 10 L per minute. The arrows show the direction of the water movement