Add a tablespoon of JOHNSON'S® Baby Oil to the baking soda. Sprinkle in the fragrance oil (I used coconut cream but you could technically add any fragrance or essential oil that's safe for use in beauty products).
Add ½ cup citric acid (you can often find citric acid in the canning section of the grocery store).
Next, add in the food coloring. The food coloring may bubble up a bit when you sprinkle it in. That's okay.
Tip: Use a spoon when mixing in the food coloring so you don't stain your hands. Once mixed, because of the ratio of food coloring to the other ingredients in the bath powder, the food coloring will NOT stain your body in the bath tub.
If you're finding the powder is clumping a bit, use a fork to break through the clumps and smooth everything out.
Continue to stir until the powder has turned a uniform color of light blue. However, there will still be little specks of green in the powder. . .and there should be!
Notes
Choose Skin-Safe Ingredients: Ensure that the fragrance oil and essential oils you use are safe for skin contact and suitable for use in bath products. Some oils may cause irritation or allergic reactions, so it's essential to select high-quality, skin-safe options. Perform a patch test if you're unsure how your skin will react to a particular fragrance or oil.
Mix Colors Carefully: When adding food coloring, start with a small amount and gradually increase until you achieve your desired color. Remember that a little goes a long way, and it's easier to darken the color than to lighten it. Be cautious not to add too much food coloring, as it could stain your bathtub or leave residue. Mix the coloring thoroughly to ensure even distribution throughout the bath powder.
Store Properly: Once you've mixed your fizzy tropical bath powder, store it in an airtight container to prevent moisture from affecting its fizziness. A jar or resealable bag works well for storage. Keep the container in a cool, dry place away from direct sunlight to maintain the potency of the fragrance and the quality of the ingredients.