I got the gallon of 30% from a friend in the chemical supply business, filled my jug from a 1000 gallon tank. You can find it online for about $40 per gallon. I also got some 40% from a beauty supply store. She would not sell me the 50% I wanted because I didn't have a beautician's license - a chemistry degree would not work, but a hairdresser can get all she wants !