I. (NH4)2SO4 2 g KCl 0.1 g K2HPO4 0.5 g MgSO4.7H2O 0.5 g Ca(NO3)2 0.01 g Distilled water 700 ml pH 1.8 - 2.0 II. FeSO4.7H2O 40 g 1 N H2SO4 2 ml Distilled water 300 ml pH 1.8 - 2.0 Adjust pH with dilute H2SO4 or KOH. Sterilize I. and II. separately, mix together and distribute the medium into sterile Erlenmeyer flasks.