Averagely Perfect ESB - Poll #34 - Specific Concentrations for Chloride and Sulfates

Someone can correct me if I'm wrong (which would be great, because I'm about to do my first run at building up from RO water this weekend), but I believe the additions will need to be split. When you use a spreadsheet like Bru'n water, you have a clear set mash addition based on the volume and it is this addition that is affecting your mash ph. If you add both mash and sparge additions to the mash, you are going to drive down your ph even more, possibly out of range, or at least not what you planned on.

From my unstanding so far, if you are using RO or distilled water, you can actually just toss the sparge addition into the boil as though both have relatively low ph to begin with, and you don't need to acidfy the sparge water.

 

That said, I guess you could also just treat the full volume of your mash/sparge water if you have that sort of room.

 

I tend to do 2/3 in the mash and 1/3 in the boil, not the sparge.