Using a pressure cooker for sterilizing vials: baking soda/distilled water???

[Wolfman99]

in the instructions for the pressure cooker I’m using, it says to add in two tablespoons of baking soda.

I did this the first time , and as obviously I’m not using the cooker for food , I wasn’t sure if it was necessary, but I did find that it left some residue on the vials.

Should you use baking soda for sterilizing in pressure cooker ?

Also, is using distilled water in the pressure cooker a must?