Combine the baking soda, citric acid, Epsom salt and beet root powder in a large bowl and mix well until combined.
Add the oils and mix again.
Slowly add the water a little at a time (it will foam a bit) and stir until the mixture is the consistency of wet sand (it should stick together when squeezed without crumbling). If needed, add more water a few drops at a time until it reaches the right consistency.
Sprinkle glitter into both sides of your molds.
Push the baking soda mixture into molds and press the sides together firmly to create a ball. Set aside for 24 hours to harden.
When dry, remove and store in air tight container or bag. If your bath bombs crumble when trying to remove them from the molds, simply pop them in the freezer for 10 minutes and try again.