Soil Black is the older version of black offered by EazyColours. It is an FDA approved batch certified dye. This dye offers an amazing black color to your bath water.
Although the water turns black it does not color your bath bomb black. At best you may be able to achieve a dark grey. To get your bath bomb black you will need to add Activated Charcoal or Black Oxide. You will need to add poly 80 for this.
There are different types of black. Some make it to look purple, this particular black was created to resemble soil. So, while your water is draining away the color will look an earthy/soil color.