The Art of Hunting
Baermannn funnels for nematodes
Collect soil samples from just about any location. Construct Baermann funnels using plastic funnel with top diamter of approximately 8cm. Attach standard aquarium silicone hose to the bottom of the funnel and clamp shut. Mount funnel on stand so that it remains vertical with the hose downwards. Create packet of soil sample by placing a small amount inside filter paper or strong kitchen towel and wrap around to enclose. Place the packet in the Baermann funnel, cover with distilled water and leave for 24 – 48 hours. Open clamp to allow a few drops of water to collect in a petri dish or similar.
There is also a Coconut Bearmann Funnel, Jugaad Staaayyle, developed in Jaaga's Hackteria Distillery.
here is a nice instruction, taken from “Low Cost Equipment for science and technology education” UNESCO, 1985 File:Tullgren apparatus.pdf
Simple Funnel Setup
Moss samples for tardigrades
Collect sun-dried moss cushions from white rocks, from natural stone walls and from terracotta roof tiles. Many tardigrades prefer calcitic stones as they need some calcite to build up their stiletto teeth. Mosses from forests are less appropriate – many tardigrades prefer mosses which become completely dry every few days and this is not the case with forest mosses. You will come across tardigrades from time to time also when screening freshwater samples from ponds. But as a rule the population density there will be much lower than in mosses. Avoid smelly and permanently damp mosses. Water bears like mosses which are free of bacteria and fungi. As a consequence it is advisable to store the collected mosses in a way that they can dry completely, e.g. you might expose your finds some time to direct sunlight or keep them in paper bags at a dry place.
by Andy Gracie, http://hackteria.org/?p=143