Figure 4. Detailed illustrations of double-netting, third section. (A) Inner side of the second net pulled down into contact with the water; (B) second net reversed totally and shaken horizontally; (C) and vertically; (D) second net pulled out of the water; (E) and washed in circular motion over the tray; (F) tray washed with the debris from the second net; (G) water in tray filtered with the net; (H) net held from the bottom; (I) and turned over the Petri dish; (J) zip-lock plastic bag filled with tap water; (K) plastic bag shaken vertically 10 consecutive times; (L) content of plastic bag filtered with the double net. Black arrows indicate the directions to shake and wash the nets and bag.