Dark Lager water help

[brownni5]

I'm working on a dark lager recipe, and am having trouble with the water profile.

4 lbs Pils
5 lbs Munich
0.5 lb Crystal 80
0.5 lb Midnight wheat
BIAB - no sparge
Bru'n Water calculator, starting with RO water

I don't have a problem getting my water chemistry to get a good mash pH, or the flavor ions right. The problem comes from the residual alkalinity - recommended above 50, but mine seems to be around or below 0 (according to the chart I'm referencing). Should I worry about RA that much? Normally I don't, but normally I brew very pale beers. Since it's a lager, I want it to be as smooth as possible. Can anyone help?

Edit: It appears the problem can be solved by shifting away from a full volume BIAB, but there must be a way to do that, shouldn't there? I have the ability, but man, a full volume BIAB is so simple!

 

[EDF713]

If your flavor ions and mash ph are fine I wouldn't worry about it. A while back I made a schwarzbier using full volume BIAB and was very happy with it. I used RO water.

It was a pretty simple recipe, here are the grain and minerals I used. I tried to get close to the bru-n water brown balanced profile, but it was a smidge higher on chloride.

7 lbs Pils
2 lbs Munich (10L)
0.5 lb Carafa (525L)
3g calcium chloride
3g gypsum

 

[brownni5]

Further diving into the Bru'n Water Knowledge tab, I see mash pH is more important than RA and a specific RA value should not be the goal. Back to a simple water profile and BIAB full volume!

I'm also very much on the fence with whether to add the Crystal malt. I like crystal in a stout or chewy Porter, but otherwise like drier beers.