what salt do you use - Tropic Marin (currently Bio Actif, before that TM Reef Pro)
how long have you used it - the Bio Actif through only 5 water changes
why do you use it - because of this (link to my gathering of info)
any noticeable difference compared to other salts that you have used in the past

I used to think Oceanic was so great but I had such horrid precipitation in my saltwater container. Tough on the pumps. After I switched to Reef Crystals and later Tropic Marin I never had that problem again.