I use 1 part of 3% H2O2 to 3 parts room temperature water. One pint H2O2 to 3 pints water comes out to half a gallon and that is enough to cover what I end up with on a harvest of one of my clones. All I am trying to do is get rid of spores from mildews and molds. If it kills an insect or two then it is a bonus.