Thanks for awakening this thread
@Ozarks Mountain Brewery, I hadn't come across it in my recent wanderings and it has bags of useful pointers (from the "big boys" in water fiddling too).
Like you, I'd been finding predicted mash pH from various "calculators" suggest too high. Contrary to this thread's title it's Bru'n Water that comes out best for me, but even it doesn't dip as low, pH-wise, as I'm experiencing. I'm trying to come up with a more "empirical" calculator (by results, not by mathematical formula). That I can then tune for my personal use; perhaps self-tune?
Currently concentrating on removing most Calcium to the boil (sparge water) in an attempt to stop the mash pH sinking so low (it is an option in Bru'n Water ... it's
not a personal fantasy which I am "known for"!). My
starting water (tap) has very low alkalinity, about 7-8ppm as CaCO
3 (about 9ppm as HCO3), lower than some "RO" waters (not that they're a "standard" even if most brewers seem to treat them as one), but I'm not convinced that makes any difference.
I'd really like to get that Mash-Made-Easy working for me, for reasons of my own I should add.