@rvan Hello. I started on 7% and never found a problem. Terri, a mentor on this site, has always advocated for nebulizing (7% being preferable) but suggested if you have difficulty with that strength try cutting back on quantity then build up to a full 4 ml when you get used to it. I think that a lesser (3 or 4%) solution is better than none. I have used it since diagnosis and it seems to have kept the bugs at bay. Alley cat Kate