Yes and yes. Some of the calcium and magnesium ions are excreted in part by the kidneys which in theory should help with specific gravity. I've never really put that much thought into dilution because it's not my cup of tea but magnesium or potassium supplements may also be good. I'll have to look into that. A couple of Tums ends up being like a calcium supplement. Don't have any Tums in them but usually Tums and Rolaids products don't contain magnesium or aluminium hydroxide. Those are more common in Maalox and Mylanta.