When you say caustic soda, you really mean lye?

Be careful in your handling of such a chemical.

Safety
Solid sodium hydroxide or solutions containing high concentrations of sodium hydroxide may cause chemical burns, permanent injury or scarring, and blindness.
Dissolution of sodium hydroxide is highly exothermic, and the resulting heat may cause heat burns or ignite flammables.
Sodium Hydroxide is extremely corrosive, and can react with fats and oils on skin, in a reaction which creates salts. For this reason, sodium hydroxide is very dangerous, and skin should be washed thoroughly with water following contact with this substance.

We got amazing results with epsom salts and a small amount of baking soda.

per 2L of water, 10tbsp of epsom salts, and 3 tbsp of baking soda.

We got some amazing results from 12V, 11.5Amperes

The bubbles were so fast and furious at the top of the jar, that it was pretty loud, and I wish we had a sealed environment to blow a balloon!