BAC water guide
Bacteriostatic water (BAC water) is sterile water with 0.9% benzyl alcohol, which slows bacterial growth so a vial can be used more than once.
BAC water vs sterile water
Sterile water has no preservative and is meant for single use. BAC water contains benzyl alcohol, so a multi-use vial is the usual choice for research reconstitution.
How long it lasts
An opened vial of BAC water is commonly used for up to 28 days. Keep it clean, capped and at room temperature or in the fridge as the label says.
How much to add
The amount sets your concentration. The water optimizer works backwards from the number of units you want each measurement to be.