Decreases pH of water. This granular product is convenient to handle, safer to store than liquid acids and has a longer shelf life. Completely soluble in water and recommended for use in vinyl pools. When broadcast into water, pH adjusts quickly. A high pH in water can impair chlorine effectiveness and cause scale build-up. 7 lb. Color code: Red. No. 042-6: Type: Granules, pH minus, Container Size: 7 lb, Pkg Qty: 1, Package Type: Bottle