I am interested in acquiring a Doncaster counting dish to count AM fungal spores since the use of the Burker-Turk or Neubauer chamber is not suitable for this. Many spores are bigger than 100 µm so they get stucked between the two glasses. Counting directly in a petri dish is not easy since you don't have a path to follow and is easy to get disoriented. Thus, the Doncaster chamber seems to be the best option but I cannot find where to buy it. Any advice about providers or alternatives? Thanks in advance.