Water softener black particles attached to salt

[timmc]

I just purchased a home with a water softener, and there are black particles attached to the salt in the tank - see attached pictures. Any idea what it is and if it's a problem? If so, should I just empty out the tank and put in fresh salt, or is further maintenance required?

Thanks!

 

[ditttohead]

Completely empty the tank of all salt and water, sanitize it with bleach and water, then add new salt. Do not risk it. Also add a small amount of bleach and a few gallons of water to the salt tank and regenerate the system to sanitize the softener.