Fig. 4. 100-L tank design. (A) External view showing the aerated gas exchange column connected to the inlet/outlet assembly via a ø25 mm tube, PVC legs supporting the tank, and airlines that lead to the aeration ring at the bottom of the central stand-pipe filter, and the gas exchange column. (B) Cross-section showing the path of water flow;water flows into the gas exchange column and into the culture chamber (arrows with solid lines), then through the mesh of the screen filter and out the stand-pipe in thecentre of the screen filter assembly (arrows with dashed lines).