Where do you get food grade CO2. I heard that the stuff from welding supply shops can have impurities in them and that food grade CO2 is better but i can't seem to find it anywhere...
Tell them it's for a home bar and they'll let you know whether or not to use it. Most places take pride in their offerings and want to make sure their customers are happy. Pick a reputable place (even if it's a few bucks more) and pay extra for the advice.