I believe it is plain ole 3% that is discussed here but I have also read to start with one pint of 3% Hydrogen Peroxide and then up the amounts as needed and I have also read about using (edit) 1.5 - 2 ounces of 35% of food grade HP but much caution is needed in handing this.
I believe this is something you will have to experiment with to get the amounts just right for you.