APEC 20&rdquo; Whole House Alkaline Calcium Mineral Replacement Water Filter pH+ (FI-PHPLUS20-BB) Neutralizes low ph and acidity in water to deliver natural water balance Adds calcium carbonate minerals to re-mineralize soft acidic water Protects Copper Plumbing from corrosion and reduces blue/Green staining 10 micron rating delivers high flow rate with low pressure drop NSF std 60 certified filter media effectively treats up to 24,000 gallons