Depending on the water softener salt used, this needs to be done at a minimum once per year. The main reason brine tanks need to be cleaned is the quality of water softener salt used. The level of impurities classifies water softener salt.

If you notice dark stains near the water line in the brine (salt) tank, you should clean it now! Those dark stains are mold. You don't want mold, fungi, or bacteria to thrive in your water softener.

Over time, sediment containing silt, heavy metals, and organic compounds can build up in your tank and start to cause your water to turn brown. Solution: Use a phosphoric acid resin clean to help flush away this build up.

When dissolved salt recrystallizes in the brine tank, it forms a thick sludge in the bottom of the water softener that prevents water from going through the regeneration cycle. Salt mushing reduces the effectiveness of the regeneration cycle, but it also creates serious blockages in the brine tank.