Question: how to make 3 hydrogen peroxide from 20 volume?
Answer: To make a gallon of 3% peroxide: In a clean gallon container, combine 1 and ¼ cups of 35% food grade hydrogen peroxide with 14 and ¾ cups of water. To make 3% hydrogen peroxide from 35% hydrogen peroxide, the general mixing guideline is: 1 part 35% hydrogen peroxide plus 11 parts water = 3% hydrogen peroxide.