This 33 000 grains water softener from Whirlpool is rated a best buy for performance and value. It features money-saving regeneration and 6th Sense technologies, which learn and predict your water usage to regenerate only when you need it. It also automatically calculates how much salt to use instead of using a fixed amount. This multi-purpose system can connect to plumbing up to 1 in in diameter and is designed to remove up to 105 grains per gallon of hardness and 9 PPM of ferrous iron. It's ideal for households of 1 to 5 people and removes high levels of water hardness and iron. This water softener is NSF certified and will help your water using appliances to operate more efficiently.