Iron is measured in ppm (parts per million) or (mgl). 19.2 gr refers to the hardness of the water. There are also many different types of iron, ferrous, ferric, iron bacteria, etc. A water softener is only designed to remove ferrous (clearwater) iron and even at that if the iron content is high, there may very well be iron that can bleed through. If any faucets, toilets are leaking this will channel hard /iron water through softener and cause staining also.