Black Algae in a Brine Tank

A brine tank is part of your home water softener system, which filters your tap water through brine in order to remove calcium and magnesium. Algae can form in your tank for a number of reasons. You'll want to remove it because it can discolor your water and give it an unpleasant taste.

  1. Causes

    • Black algae can form in your tank if your unit has been inactive for a few months. Layers of algae also form in tanks placed in direct sunlight in warm climates, such as Florida's. If neither of these situations applies to your tank, you may have a broken valve that is allowing oxygen and dirt to enter your tank.

    Clean Your Tank

    • Temporarily turn off any other water treatment equipment you own. Run a manual regeneration cycle to flush the water softener. Add one to two cups of bleach to the brine tank to kill the algae and sanitize the tank. Run an extra manual water softener recharge cycle to flush the bleach through the system.

    Repair Your Tank

    • If your tank was stagnant for a long time, cleaning it should clear the algae and sanitize the unit. If your tank is in warm, direct sunlight, you may need to replace the resins in your unit, which can become embrittled under these conditions. If you don't know what could be causing the algae and it returns after you clean it, you need to have your unit serviced by a professional.