I am experimenting. I have one in my bedroom that is 50/50 Perfumer's Alcohol/FO that at times is doing pretty good. Other times I don't seem to smell it much. I have another one in my bathroom that is 50/50 IPM/FO and it actually seems to be doing a little better. I also stumbled upon this info on a supplier's website: Heyxlene Glycol is combined with fragrance oil when making reed diffusers. Hexylene glycol will not only lower the cost, since it's less expensive than most fragrance oils, but also dilute the fragrance oil without detracting from the strength of the scent throw (in fact, the manufacturer says it enhances throw with most FO's!). SUGGESTED USAGE RATIO: The manufacturer suggests a ratio of roughly 1 part FO to 2 parts hexylene glycol. We suggest you experiment with your own FO's, starting with equal parts FO and hexylene glycol, and evaluating the scent throw. *** As seen and demonstrated at the 2005 Chicago-Area Soap and Candlemakers' Conference! *** I found this at www.oakcourtcreations.com but I have no idea personally if it works.