Following a discussion I had the other day, with another stylist I was a little confused, I was wondering if anyone can clear this up for me. We had ran out of 6% (20 vol) peroxide an she wanted to water 12% (40 vol) down to make it, I know from my theory lessons many moons ago that you can do this by using equal parts of distilled water an 12%. She then asked if she had ran out of 12% an wanted to make some using 6% could this be done by just using double the amount of 6%? I wasn't sure, does anyone know? Thanks in advance