We have a lot of iron in the water (very common in my area). In 23 yrs. we've "dealt with it" (regularly clean the screens on the hoses to the washer, irrigation, foregone white shirts/sheets/slipcovers, and do the CLR thing on the fixtures in the johns, etc.). We got a price for a treatment system about a month ago... I almost fell over, just under 4K. Treatment involves 2 tanks, a salt catalyst that must be replenished periodically (for us, every 2 mos.), and the used brine is discharged into the septic system. Should we be concerned about discharging brine into the tank? will it wreck the whole bio-system that is supposed to take place in the tank?