Bru'n Water -- sparge acidification in dark beer?

Working out a brown porter recipe in Bru’n Water,  and while I really need no adjustments to source water (might still raise mash Ca and pH a wee bit with pickling lime,)  Bru’n Water is showing sparge acidification on the adjustment sheet.  Is this really a necessary recommendation, or just displayed as an automatic result of having initially filled out the sparge acidification sheet?  Bicarbonate is ~100ppm, predicted mash pH with no water adjustment 5.33.  Thanks in advance.

Rob, if that was a paler beer, I’d definitely say that the alkalinity in your tap water should be neutralized to avoid tannin and color darkening effects. But in a darker style and your modest tap water alkalinity, it may not be necessary.

The good thing is that your water doesn’t require much acid for neutralization.