I'm planning on brewing an AG partial boil. 3.5gal boil, 5.5gal final vol (i.e. 2 gal top-off water). I'm using all RO water and doing salt additions. Do I calculate for, and thus treat, ALL 5.5 gal of water (thus, including the top-off water), or only the water for my Mash/Sparge? I've seen some opinions both ways. Thanks for the help!