• Prevents bacterial and fungal growth in membranes during long-term storage
  • Compatible with thin film polyamide, polysulfone, PVDF and cellulose acetate membranes
  • Certified by NSF to NSF/ANSI Standard 60 for use in potable systems

Typical Properties

  • Appearance: White crystalline powder
  • Odor: Pungent, characteristic
  • pH (1% solution): 7 – 9
  • Solubility in water: Complete


  • 50 lb. pails and 400 lb. non-returnable plastic drums

Safety and Handling

Store in cool, dry and well-ventiled area. Keep containers closed. Avoid breathing dust. Do not get in eyes, on skin or clothing. Wash contaminated clothes before re-use. Wash hands thoroughly after handling. For more information, see the Safety Data Sheet provided with this product.

Chemical Feeding and Control

The water used to prepare the solution must be free of residual chlorine or other oxidizing agents. Best results will be achieved by using RO permeate. The recommended solution for membrane preservation consists of 1 wt% C-221 in water. This solution can be used as membrane preservative for up to 6 months.