Plankton Net
![network list](/curious.bio/planktoscope/media/commit/2ae26d82c10133a8b7dcc4c39c80cebd5ee832b5/docs/images/hardware/planktoscope_collecting_device.png)
The simplest device you can use is a plankton net. It should be made of a fine mesh, down to 20 micron. It can be towed behind a boat at low speed (less than 2 knots) or towed by hand in a river or a lake.
Plankton nets can be made easily with a good sewind machine and some hardware.