I have a Puronics water softener. The people coming out to replenish my salt supply and check the unit keep telling me that I should get a new Bacteriostatic Hygene at a cost of $389.95. I question the need for this unit or whatever it is. The water softener is just doing a so-so job, but the perceived hardness of our water hasn't changed, so why do I need to invest in this expensive part? Can anyone tell me whether or not I need this thing?