True to start out at least and for most people always. After you have brewed with the lowest sulfate level you can get try adding a pinch of gypsum in the glass to see if you are one of those who likes a bit of sulfate in his lager. But do not use gypsum with this water to increase calcium as it will add sulfate. Also, don't add any epsom salts as that will add sulfate.



You can get by with levels lower than 30 certainly and you will probably want to do that as your only route for higher calcium is calcium chloride and you don't have that much headroom for chloride with the base water at 50 already. Try to keep chloride below 100 to start out but again you can add more in the glass to see if you can tolerate it. Otherwise, you would have to dilute down with RO to 'get rid' of the chloride and then build back up with straight calcium chloride.



You can do this but you are adding calcium bicarbonate. The bicarbonate contributes alkalinity to the water and you don't want that especially as you are blessed with a low alkalinity source. Also a PITA.



You will also need some acid, probably most conveniently in the form of a couple % w/w sauermalz in the grist. Alternatives are lactic or phosphoric acid both available from your LHBS.