Into your mixing bowl, add in all the dry ingredients (citric acid, baking soda, and mica). Combine well with a whisk.
Add the entire polysorbate 80 and stir to combine.
Add your fragrance. Your kit may have come with two 1 dram or one 2 dram bottle. Use your hands to mix further and ensure the mixture and coloring is even with no lumps.
If the mixture is too dry, spray the bath bomb mixture with a bit of Witch Hazel Distillate.
Test the bath bomb consistency by squeezing a little bit of the mixture in the palm of your hand and releasing it into the bowl. Does the mixture stay compact and in shape or does it crumble? If it's the former, the mixture is ready to mold. If it's the latter, spray a little Witch Hazel Distillate and try again.
Fill your bath bomb mold with the mixture a little at a time using some pressure.
Gently release the bath bomb from the mold and place it on your counter. Allow to dry for 24-48 hours.