I have had two new one gallon tanks, with no problems.They also run my Mr. heater. New tanks have to be purged before they fill them for the first time. It sometimes supprises that some of the people filling these, can even figure out how to put gas in there car. If your tanks have not been purged, I am sure that is your problem. You might also want to take tank and heater to a propane company and have them check it out.