A  1L  of well water which consists of magnesium was made basic with KOH,  which precipitated most of the magnesium as magnesium hydroxide.  The product was then titrated with  20,21  mL of  0,01123  M EDTA using a culminate indicator,  which is the  EDTA  indicator.  Calculate the  water  hardness  in  terms  of  MgSO4  in  ppb.