the coral and such are generally saved for SW tanks. the list above was targeted for FW as i have 0 experience with SW. but there are some instances where the coral would be ok to use. a few that would come to mind is if you have very hard tap water (ie well water in many cases) or if you where keeping african cichlids and wanted to match the ph and hardness to their natural habitat. but in most cases stay away from them in FW uses.