... etching caused by low alkalinity. Stabilizes pH balance in pool water and eliminates the demand for unusually large amounts of pH adjusters ... (or 2lb),2kg (or 5lb),3kg,4kg (or 10lb),8kg and 10kg of Pillow Bags, Doy Packs,Gusseted Bags.0.5kg ... (or 2lb), 2kg (or 5lb), 3kg, 4kg (or 10lb), 8kg and 10kg of Pails, Jars, Jugs, Pots, Tubes, Drums ...