The "sharp" smell of acidic rapid fixers like Ilford Rapid isn't because of the ammonium content in them, but because of the acetic acid and bisulfites/metabisulfites in them. Alkaline rapid fixers on the other hand can smell like ammonia AFAIK. The difference is in the pH of the solution. Alkaline pH makes them smell so. Oh and it's a good idea to use gloves when handling selenium toner. Additionally, make sure you clean any spills very well. It's not just that it's quite nasty stuff, it also *stains* evrything.

