I have purchased Reed Diffusers in the past and love the aroma from them. but they seem to evaporate so fast. Is it possible to make my own aromas? I checked bottles of Lavender, Spearmint, etc at a health food store, but they didn’t seem to know of a recipe to use it. Do you? Also where is the best place to purchase them.? I thought the price was a bit expensive at the health food store.