All the media have several components in common : sources of nitrogen, phosphorus, vitamins and trace metals. However the specific types of these nutrients, their concentrations and ratios vary between the media. Some media used in ANACC have been developed by us over many years, for instance our medium of choice for freshwater cyanobacteria is MLA (Bolch and Blackburn, 1996) which is a modification of the ASM media developed by Gorham et al (1964). Some media have relatively unusual trace metals such as selenium in GSe (A modification of GPM, Loeblich, 1975 and vanadium in MJ medium. Because of their unusual nature it may be tempting to leave these out if stocks are difficult to come by but this would defeat the very purpose of the media. Detailed descriptions of the common nutrients, buffers and chelators can be found on Major Nutrients and Other Nutrient components.