BRT LArval rearing system I have finished my larval system. It has a BRT (Black round tub) larval tank, hooked to a 50 gal sump and skimmer. The BRT has a central standpipe with a bubble ring on the bottom. This keeps the larva suspended in a kreisel type current and off the wall. The central standpipe can be adjusted for height to control larval volume. The central filter is removable for cleaning and is wrapped in 250 micron cloth. The water delivery to the BRT from the sump is designed to be very slow. I emerges just below the bubble ring and is part of the up flow. My goal is to cycle the larval water every 1-2 days. This a drip at best. The BRT drain is 1/4 tubing and it terminates in the sump above water so I can count the drops to estimate the turnover rate. Both tanks require heaters because of the extremely slow turnover rate. I am now waiting to establish the next Neon Goby fry date and I will fill the larval system from the brood stock system and see how it goes.