house constructed in 2000. Copper water lines. Softener installed at original construction. Recently began to get deposits in faucet filters - the ones at the end of the faucet inside the aerator. Deposits are similar to small salt granules, but do not taste like salt. Show up in all faucets. Softener seller was out and says deposits due to reaction between copper water lines running adjacent to or under air ducts from HVAC system. Doesn't make sense to me as some of the most significant deposits are in a faucet in workroom sink next to water heater. Supply lines never get close to any air ducts. anyone have alternate theories? Thanks!!