the cheapest way would be household vinegar or citric acit to lower it as you done succesfully, just us plain vinegar and not the fancy one
the water hardness come from minerals solved in your tape water and partly from the chlorine. to get of wide of those you boiled of the water and let it sit then, hot water can dissolve less of those minerals and chlorine so the gas/fall out, just let it sit, run it thru osmosis filter systems or get a water softening system for your house, funnily those work as well with salts
