Pfizer Hospira Bacteriostatic Water 30 mL Peptide Test How to Store Bacteriostatic Water Safely Confused about whether BAC water needs refrigeration after opening? According to USP standards and Pfizer's own guidance, both room temp (2025C) and refrigeration are acceptable Bacteriostatic Water 20ml x 1 QTY (Bac Water) Bacteriostatic Water USA 30ml Bacteriostatic Water (each) Bacteriostaticwater.com How much BAC water should you use? It depends There is no one size fits all answer. Different vials may need different amounts of BAC water depending on how strong you want the final mix