What volumes of Mash and Sparge water are involved here. And how much grist is involved?

I hope you sent off pre-softener water to be tested. Water softeners replace Calcium and Magnesium ions with Sodium ions. Water Softeners do not impact (alter) Alkalinity, Sulfate, or Chloride. BTW, that's a mighty fine brewing rig you have there!

You could always take up the hobby of maintaining a salt water fish tank (complete with live fish).

But it won't be right when alcohol is present. And the FG conversion calculators are scaled to sugar refractometers.

Looks like you bought a salinity refractometer. I'd assume it measures salt density as Brix. What you want is a sugar refractometer.

True! Indeed you can't say that one is more bittering than the other when their AA's are equal. All you can say is that one form (pellets) gets there much faster than the various of leaf/whole hop types. Pellets will convert all of their AA's (that are possible to convert) into IBU's within...

That is merely a misnomer that has been parroted so frequently that it has falsely become true to most homebrewers.

Bingo! Oxnomore https://www.enolife.it/linea-oxnomore/

Where does one get their hands on some "Oxnomore super"?

https://www.mdpi.com/2304-8158/9/11/1638/htm

When I think of tannins, I'm thinking about beneficial antioxidants. Do a search including the terms "tannins antioxidants brewing".

I'm of the opinion that 5.5-5.6 is a good mash pH, and if you add baking soda whereby to hit a nominal targeted 5.55 mash pH, along with leaving the deep roasted malts/grains in the mash, your deep roast malts will not cause the problem that concerns you. Oatmeal is not (in my opinion) going to...

Of course BC could also be specific to temperature (in addition to being specific to target pH). It is well known that weak acids are more acidic (they liberate more H+ ions, reflecting highly altered Ka/pKa dissociation "constants") when placed within an environment that is more 'hot'. The...

Reflecting upon this further, BC is a 'units applied' quantification of a grists ability to resist change in pH. As acid (or base for the case of deep roast and/or caramel/crystal rich grists) is added, the grists ability to resist change in pH is eroded and diminished. This is effectively the...

The reason why the above yields only a "better bet" as to the second acid addition is that BC itself is highly pH specific, and most 'given' BC's are specific to only pH 5.40, and are really not correct or valid for application at pH 5.10. Therefore even the above "better bet" is flawed. And...

The thing that the above data negates is using conventional mash pH assistant software to target knockout pH via a method that appears rather common. And this is the reason why: The common yet failed method which I'm alluding to calls for using said software to calculate two separate acid...

Applying the above equation yields projections of: 1) A Wort which starts the boil at a room temp. pH of 5.20 should exit the boil at pH ~5.12. Drop = ~0.08 pts. 2) A Wort which starts the boil at a room temp. pH of 5.10 should exit the boil at pH ~5.06. Drop = ~0.04 pts. 3) A Wort which starts...

I dug through Wiley Online and came across this 1975 brewing research document (see link below). See Table XI on page 68 at the bottom left. It shows that in their tests: 1) A Wort which started the boil at a room temp. pH of 5.78 exited the boil at pH 5.48. Drop = 0.30 pts. 2) A Wort which...

We could go back to Kolbach's 1950's attempt to predict, target, and thereby be capable of advanced modification of knockout pH. His chosen calcium and magnesium "divisors" are probably much closer to the truth for knockout (I.E., post boil and cooling) pH conditions than they ever would be...

If you mash a grist in DI or distilled water and it's mash pH is measured to be (for example) 5.62, and you mash the very same quantity of the exact same grist in the exact same volume of a water that contains both alkalinity and free (or dissociated) calcium ions, and you also for this water...