The original poster was foliar feeding, misting, with vinegar, something i would never consider. Watering with vinegar is safer but when average cup of coffee has a ph of 5, my preference for either.
Depends on what grocery store you go. My stores carry Topo Chico, Mountain Valley, or Pelegrino. They are like $1.50 for 750mL. Not sure if you want to spend that every time you water. Ask for sparkling water.
A one liter bottle will literally last a lifetime!! It's like 0-55-0......crazy concentrated! So much it will burn your skin! Has to be diluted to use.
My bottle is like over 5 years old! And it's still almost full!