I use R.O. water and adjust it to the area the beer is known for with Beer Smith2. Reviewing Palmer's How to Brew. I came across brewers in Pilsen using an acid rest to help the enzyme phytase acidify in the mash. Phytase breaks down phytin into insoluble calcium, magnesium phosphates and myo-inositol (a vitamin). I add calcium and mag, but no inositol. Has anyone added this? If so how much?