not to be difficult or argumentative, but the amount of iron in the YPS (Yellow Prussiate of Soda) is so minimal that although there is a slight chance of staining, it would be due to the salt not being stirred around to dissolve. If it sits on the bottom of the pool without being stirred around, there is a potential staining that may occur. However, stain remover will help get rid of it.

My reason for saying this is that for YEARS before there was "Pool Salt", guess what salt we used? Food Grade Table/Granular salt with YPS!