I'm about to embark down the RO water lane and also use brewers friend. I've been reading the Water book and its definitely has tought me a lot. There are many more styles listed (and reasons for different ion concentrations) that what brewersfriend lists. So you're a step ahead of me, but I've been coming to the same question (I'm assuming). What is the best way to make water from RO? What software/style (mineral additions) should I try for?
I haven't comared brewersfriends calculations to any of the other popular water software, but according to the Water literature, I was getting similar additions to reach a certain concentration with a few things I checked (this by no way means brewersfriend is accurate, I will wait until I test it's predictability with a pH pen on brew day). But at least it passes the sniff test.
And now lets talk about the light and hoppy profile. BF lists it as:
Ca|-Mg-|-Na-|-Cl-|-SO4-|-HCO
75|---5--|-10-|-50-|-150-|---0---
The water book listes for "American Pale, American XPA, Saison, American IPA, Double IPA" as:
----Ca-----|-Mg-|-Na-|----Cl----|-----SO4---|---HCO
50-150 |--------|-------| 0-100 | 100-400 | 40-120
And this is where I've gotten. I know there were some minimum values listed for Mg and Na but I need to re-read this section. Also, I need to reread about the different ranges and what is optimal for varoius conditions. But you can tell there are definitely some differences between these profiles. I'm sure someone with better knowledge and finish what I started and make recomendations.