Destructable color

I made a custom destructable using circle of power model, the problem is that every one of them i placed on the map ended up being the player color in the first slot

How do i make them black?

Assuming you mean team color, change the owner to one of the neutral players.

Edit: Nevermind I thought it was a custom unit.

Try modifying the "tinting color" of your destructible in the object editor.