The most important is to make sure that your toner doesn't contain any irritant agent like fragrance or alcohol. Then, also avoid any scalp treatment (toner or else) that includes oils as this will feed your dandruff and make it worse. We have found that using Rose Water has worked wonders for some students as a scalp toner as it is very light but also hydrating! Sarah uses Rose Water from a brand called Alteya which seems to be 100% Rose Water! Do look into it as there are apparently some great scalp benefits for Rose Water. If you do decide to by it though, try a small bottle first, just in case it doesn't work out for you!