water chemistry and stout help

Following up from a few weeks ago now that gravity is stable on a big stout that didn't turn out as big. Just received ward labs well water report today and hope this will improve my extraction efficiency for future stouts.

Stout brewed 3 weeks ago or so:

Part 1. Mash pH of stout brewed was about 4.6 (almost 50% MO and the rest specialty malts) ~ TEMP adjusted mash temp152-154 even lower so around 4.25. This Is definitely too low for some enzymatic activity right? I want to be in the 5.2-5.6 range correct?

Post boil pH if it matters was 4.92 at room temp)

Fast forward to today took the plunge to get into water chemistry since I love a challenge and here's my well profile:

pH 6.8
Na+ 14
K+ 5
Ca 39
Mg 11
SO4 7
Cl 36
HCO3 107
total alk 88
total hardness 143

So with this info looks like my RA is about 57ish base malt pH about 5.8. ( I feel like this is pretty accurate based off a previous Berliner with mash pH of 5.6 with germ pils and wheat malt) As we all know this isn't what I am looking for though with all those acidic specialty malts for a stout.

So to put it all together if I were to brew the same recipe again looks like I need to go up about a full point more basic to bring the mash within proper pH range for proper conversion. Does this sound correct?

Messing around with the Brisbane brewers RA nomograph my additions of chalk and baking soda seem pretty ridiculous and take the HCO3 through the roof not even putting me close to where I need to be. I am assuming dilution with distilled water and boiling off help those values a bit for the final product.

Any idea how much boil time affects the values of Ca and HC03? Also concerns to worry about when diluting with distilled water?

Also re-reading to how to brew as I type (specifically reading a water report section) is it safe to say you can go overboard with Ca and HCO3 in your mash and just adjust with the boil and distilled water or do you have to worry about something like chelation if you use too much in the mash?

Any help is greatly appreciated and I can provide more info if needed.
Forever in pursuit of brewing a better beer.....

 

Yeah after this post I went through my brew cipher recipe entered my well values and it came back with a mash pH of 5.2. Which I measured with my meter and definitely did not get that value. So I'm confused!!

 

That's some great info will definitely plug those additions in. I've been reading a lot and seems as though there are mixed views on mash pH for a stout vs. extraction efficiency. my biggest concern is trying to figure where in the process am I messing up and didn't know if there will be a significant difference in OG (increase ) if i brew the same stout again.Next time increasing the water pH although might have to do a third time since pH meter may not have been calibrated. (Stole some calibrating solution from work this week)

 

Here's the grain bill was going for big first running stout super roasty at the forefront

43% MO
1% c120
4% c60
16% roast barley
12% Choclate malt
8% black patent
15% flaked barley

For next time already considering increasing the MO and decreasing black patent and crystals slightly