Fig. 2

Exploded diagram showing the main components of the aquatic system and fluid flow. Various parts are as labeled. The various valves are also labeled and/or numbered, as referred to in the text and Figure S2 in Additional file 1, SOP. Parts are shown in their relative, approximate locations but are not drawn to scale. Blue arrows show the main routes of the seawater flow. The size of the arrows indicates the relative amount of flow through the various passage ways. The electromechanical 3-way valve can divert seawater either to the right towards the filters during the filtering mode or to the left through the feeding bypass loop during the feeding mode. Green arrows show the delivery of food and flow of seawater through the feeding bypass loop. The one-way check valve prevents seawater containing food from traveling backwards through the filters during the feeding mode. Brown arrows show the return of seawater collected in the drain troughs that travels back to the sump via the drain pipes and slotted diverter. Orange arrows show the flow of seawater, RODI water, and other reagents that are periodically added to the system (sump). The bypass valve #5 can be opened to prevent pump cavitation and to reduce the flow of water to the tanks, as needed. So far, we have not had to use the UV lamp or the second pH/calcium dosing pump (calcium supplements have been added to the system manually). The feeding system and its associated parts (e.g., sensors) are not shown here