Plankton filter design
The plankton filter is made from plastic, we try to avoid plastic but in this case there are not many options, just dont drop it in the water or throw it away. If you no longer wish to collect plankton samples, then give it to another yacht.
You may use PVC, ABS or polyethylene plastic, you could also use aluminium or stainless steel. The following is an explanation how to make the PVC or ABS plastic version of the GOES plankton sampler which was designed by Dr. Jesus Ramon Barriuso Diez.
1 x 50mm female threaded socket
2 x 50mm male part/threaded nipple
1 x 50mm plain socket
225mm of 50mm pvc pipe
1 x pot of pvc glue, with small brush
50mm diameter 100 um plastic mesh. use the pipe as a template to cut out a disc
1. place the 50mm diameter mesh over the end of the p/t nipple and screw it into the t/t socket until the mesh is securely held at the centre of the socket. Drill a 5mm hole near the base of the p/t nipple
2. 250ml locking pipe, Glue the second p/t nipple into the plain socket, and glue the 200mm of pipe into the other side of the socket. Leave for 24 hours to set.
3. Place the 1 um filter paper into the filter, and secure it in place using the 250ml locking pipe.
Calibrating the filter.
With the filter paper in the Plankton filter, measure out 500ml of water with an accurate measuring jug, or weight out 500g of freshwater. Quickly pour it into the filter, the water level should come up to the rim of the pipe. If the water level sits under the rim, carefully saw the pipe to reduce its length to be in-line with the water level immediately after it was poured into the filter