Nomograph understanding help
I have analysis of my water:
Ca: 53 ppm
Mg: 25 ppm
HCO3: 260 ppm
Alkalinity as CaCO3: 213 ppm
And I did used nomograph from John Palmer to determine what beer best suite to water I have. And I get Residual Alkalinity as CaCO3 about 165 ppm and Mash pH about 5,95.
And I don't understand the mash pH meaning. I am confused because pH from Analysis is 8,5, in nomograph I get pH 5,95 and as I know I should end up at the end at 5,2 to 5,6.
So I would kindly ask someone to explain me the meaning of mash pH I get from nomograph.
Is this pH I get when I put barley malt to the water?
Is this pH something I should have before mashing - should I lower the pH prior mashing?
Thanks in advance.