I have bought some hydrogen peroxide but it says 35% (food grade) on the container. have i purchased the wrong stuff as it mentions 3% in a earlier paragraph? thanks for your time.
No you bought a correct brand. Just add 10 parts water to 1 parts 35% H2O2, and you should get about 3% H2O2.Or 35%/11 = 3.18% H2O2.