We have been seeing a lot of really dirty filters lately in the Birmingham, AL area. The filters pictured here are from homes without a water softener. If you have a reverse osmosis system in your home but do not have a whole house water softener, your reverse osmosis system may be working harder than you think. Calcium and magnesium are two of the hardest minerals for the reverse osmosis membrane to remove; however, the sodium that is added to the water by the softener is much easier on the membrane. Because of this, a water softener will help extend the life of the membrane and filters.