BOD dilution H20- any help from a lab chemist?

how many ml each of MgSO4sol'n 2.25%, phosphate buffer pH 7.2, CaCl2 sol'n2.75%, & FeCl3 sol'n 2.5% in the preparation of a liter of BOD dilution H2O. Also, do i need to adjust the pH of the sample in the BOD bottles? what pH? how? any help would be highly appreciated..... thanks..