Could use some help with Bru'n Water for an American Porter

I've only done a couple batches using Bru'n Water so still getting the hang of it.

Was hoping somebody could look this over so I don't screw up a batch before I even start.

Going to brew a Founders style Porter tomorrow...will end up being a 6 gallon batch. Total water is just over 10 gallons.

I could get RO water if needed or I could use my Chicago water with a campden tablet.

I'm leaning towards my tap water but I'm trying to figure out how to get my mash PH up... I added .5g of baking soda however why is it showing red? Is it just because I shouldn't add it to the sparge water?

Also, why is the bicarbonate NAd?

Would I be better off getting RO water and treating from there?

Any help is appreciated.

Another question I have with Bru'n Water...If the Final Water Alkalinity in the sparge acidification tab is at 21 with no dilution and PH set to 5.8, can I safely ignore this tab moving fwd?