• NH₄Cl 0.1 g
• KH₂PO₄ 3.0 g
• MgCl₂.6H₂O 0.1 g
• CaCl₂ 0.1 g
• Na₂S₂O₃ 5.0 g
• Bidistilled water (or fresh distilled water) 1 L

Dissolve all the ingredients and adjust pH to 4.2 with 1N HCl. Dispense into screw-capped bottles.

For solid medium dissolve the ingredients in half of the water volume required. In the rest of the water dissolve 20 g/L of agar. Sterilize separately at 120 °C for 20 min. Mix them and dispense aseptically in tubes or plates when still hot.