Features: Longevity: the cartridge alone will treat approximately 30,000 gallons of water (depending on water conditions) NSF Certification to meet NSF/ANSI Standard 60 for drinking water additives Efficiency: sequesters hard water and low levels of iron, reducing scale build up and hard water rust staining. Odorless Non-hazardous by WHMIS/OSHA criteria Consumer Note: When the cartridge reaches the 30,000 gallon capacity, do not buy a new cartridge. Instead, purchase the Pro Poly Guard Crystals to refill your cartridge again and again! View Pro Poly Guard Crystals HERE Specifications: Comes in a 6-pack of 1.5 lb size cartridges Fits a 10" standard whole house filter housing Temperature range: 40-125 F Melting point: 1200 F pH: 7 (1% solution) Appearance/Form: Glass-like/Crystals Applications: Reduces scale build up and hard water rust staining Applicable to plumbing and water-using appliances Drinking water- reduces the leaching of copper and lead into drinking water Corrosion Control: The cartridge will hold 1.5 pounds of crystal and treat up to 30,000 gallons of water. These crystals will not dissolve completely and should be replaced in 30,000 gallon intervals or every 6 months to ensure product efficiency.