How to collect a plankton sample
Prepare the plankton filter be inserting a new 500mm filter mesh disc into the Plankton filter.
It is going to take about 30 minutes to filter the sample, so find a location and secure the plankton filter in a vertical position. Water is going to be draining out of the bottom of the filter, so best to do this in a sink, or the cockpit, or anywhere that allows the water to drain to waste.
Using a clean bucket, with a volume greater than 500ml, attach the container to a cord and drop it over the side of the boat to collect the water sample. Once the sample is back onboard, pour the water quickly into the Plankton filter, fill it up to the top till it over-flows. The plankton sampler only contains 500ml, so if it is filled over-flowing you know you have the correct volume. Now just leave the filter for at least 30 minutes to allow the water to pass through the filter paper by gravity. It may take a bit longer than 30 minutes in some cases, especially if you have caught a gelatinous plankton such as a sea gooseberry.
Once all the water has passed through the filter paper, and there is no more surface water visible on top of the paper, transfer the paper to a clean dish or petri plate, and place under the microscope.