A: We offer free of charge stock samples under 1KG, if you need special samples, please Call us and we could connect. Poly Aluminium Chloride achieves this by generating hydroxyl ions and polyvalent anionic polymers, which aid the coagulation and flocculation of suspended particles to improve h2o top quality. Coagulation: https://www.pac-pfs.com/product/drinking-grade-polyaluminium-chloride.html