NATURAL SEAWATER-BASED PRO99 MEDIUM
Prepare a glass filter funnel and flask by cleaning with acid and Milli-Q water. 
Filter raw seawater through 47mm Whatman GF/F stacked on top of a 47mm 0.2µm polycarbonate filter. 
Autoclave seawater in a Teflon bottle (60 minutes for 2L). 
Allow to cool overnight. 
Prepare 0.5M NH4Cl solution. 
Prepare 0.025M NaH2PO4·H2O solution. 
Prepare primary trace metal stocks. 
Prepare trace metal working stock. 
To make up the media, add following volumes of sterile nutrients and trace metal stock to one liter of the autoclaved seawater.
NutrientVolumeFiltered Seawater   1000.0mL0.5M NH4Cl   1.6mL0.025M NaH2PO4·H2O    2.0mLTrace metal working stock   100µL. 
Store at room temperature for up to one month.
