We are installing a new gas line using the "gastite" fittings for the first time. We have a 15 lb gauge that has been pressurized to 10 lbs. It will stay at 10 lbs for the day, but when we come back in a week it will be down to 6-8 lbs. We have soaped the fittings several times over many weeks and can't find a leak. Is this normal for these fittings? Is the leak enough to worry about? Is there a better way to check besides soaping the fittings?