1. Combine the following in 900ml water:
   • 1ml Phenol Red (0.04 %)
   • 10ml FeSO₄/EDTA solution (see below)
   • 11.92g HEPES buffer (Sigma H-3375)
   • 0.5g NaCl
   • 20mg CaCl₂ × 2 H₂O
   • 40mg MgSO₄ × 7 H₂O
   • 0.2g KH₂PO₄
   • 0.5g (NH₄)₂SO₄
2. Adjust to 1000ml with water
3. Autoclave or filter sterilize.

FeSO₄/EDTA solution:

1. Combine the following in 100ml distilled water:
   • 19mg EDTA
   • 18mg FeSO₄ × 7 H₂O
2. Autoclave or filter sterilize.