Why is my humidifier forming black percipitate in the tank? how can i remedy this

The black percipitate is common to this unit it is from hard water the heating element is what causes it you can take it apart to clean it or just tap it gently to get the dabree out of the unit that has the heating element in it.

The black particles are pretty common. This is a byproduct from minerals in the water and is normal.
Just clean the tank regularly (with diluted bleach). The black particles will also collect in the steamer unit (the top blue part). Wash this out with hot water (no soap or anything) after each use. If you tap it a few times on the floor of your bathtub you'll probably see some of this black stuff come out. No worries, just rinse again with hot water.
There's no harm from the black particles.

I have two units: one 2 years old and one 0.5 years old. Only the newest model causes the black water issue (both use same water source). Vicks must've changed the heating element coating and inadvertently caused this problem. I recommend reporting it to their customer service number.

My vicks humidifer does the same thing and its brand new. must be stuff in the water